What does a baby's fetus look like at one month old? Fetal development by week of pregnancy, clear description of each month with photographs

Every woman dreams of becoming a mother. From the first weeks of pregnancy, when life is just beginning, we look forward to meeting the baby. How nice it is to hug this warm little bundle, hold it close and never let go. However, it will be nine long months before the mother and baby meet.

How many weeks can pregnancy last?

It is generally accepted that a normal pregnancy lasts 9 months or 40 weeks. Permissible deviations are the birth of a child from 37 to 43 weeks. Babies born before 37 weeks are considered premature, and after 43 - post-term.

According to statistics, only 4% of women give birth exactly on time, and about 70% give birth with a deviation of 10 days before or after the scheduled date.

Research conducted by specialists from the National Institute of Health and the Environment in Durham, USA, has proven that such a difference in timing depends on a number of factors.

Pregnancies last longer for older women, with each year of a woman's age adding one day to her pregnancy.

Women who weighed more at birth carried their babies longer. Experts calculated that every 100 grams of a mother's birth weight added one day to her pregnancy.

Finally, if a woman’s previous pregnancies lasted longer than the average term, then the subsequent pregnancy was longer.

Human Reproduction magazine

When does the first week countdown begin?

From the moment of birth, each girl’s body stores a huge, about 400 thousand, “reserve” of eggs, which are in an immature state in the ovaries. During development, some eggs die, while others grow and acquire the ability to fertilize.

From the moment of puberty until the onset of menopause, the eggs mature in turn and are released from the ovaries into the cavity of the fallopian tubes, where they wait to meet the sperm. If the meeting takes place, fertilization occurs and a new cell is formed, which, if successfully developed, will turn into a little man in nine months. The sperm rushes to fertilize the egg

There are several concepts of pregnancy counting:

1. Obstetric week of pregnancy, which depends on menstrual cycle women. Its countdown begins from the first day of the last menstruation in the conception cycle. From the first day of the last menstruation, 40 weeks are counted and the approximate date of birth of the baby is obtained.
2. A week from conception. As a rule, this is already the third obstetric week and depends on the timing of ovulation, i.e. whether the woman ovulated early or late.
3. One week from missed period. This is already the fifth obstetric week. During this period, the woman already shows the first signs of pregnancy.

They say that this is almost impossible, but from the first day of pregnancy I knew that life was being born in me. Probably I had a very strong connection with my future son, or I really wanted to get pregnant, but the very next day after intimacy with my husband, I was one hundred percent sure that I was pregnant. My premonitions did not let me down and nine months later I gave birth to a wonderful son.

From what week is pregnancy considered full-term and birth considered urgent?

At 37 weeks of pregnancy, the child is already ready for independent life. All the baby’s organs are already formed, the lungs are ready for breathing and the body can exist outside the mother’s body. Therefore, if a child is born at 37 weeks of pregnancy, then such a pregnancy is considered full-term, and the birth is termed, i.e. the birth occurred on time or on time.

Scheme of the relationship between trimesters, months and weeks of pregnancy

Pregnancy is counted by months or weeks. So, the average duration of pregnancy is 3 trimesters, or 9 months, or 40 weeks.

Table: ratio of trimesters, months and weeks of pregnancy

Trimester	Month	A week
1	0	0	1	2	3	4
	1	5	6	7	8
	2	9	10	11	12
	3	13
2	3		14	15	16	17
	4	18	19	20	21
	5	22	23	24	25
	6	26	27
3	6			28	29	30
	7	31	32	33	34
	8	35	36	37	38
	9	39	40	41	42

Calendar of important weeks of pregnancy

A pregnant woman, keeping a pregnancy calendar, will not miss a single important moment and will receive answers to many of her questions: when will her belly begin to grow, when will the baby move for the first time, etc. After all, over the course of 40 weeks, the baby grows and develops, and you need to watch out for any deviations in the development of the fetus. To do this, you need to do an ultrasound on time, undergo screening and tests.

When do you need to register with an antenatal clinic?

In order to receive qualified medical care throughout pregnancy, the expectant mother must register with the antenatal clinic. This will ensure constant monitoring of the child’s development and the course of pregnancy. Visiting a doctor and following all his recommendations will help identify pathology or disease of the fetus in the early stages, start treatment on time or carry out prevention.

By registering before the 12th week of pregnancy, the expectant mother will also receive one-time assistance for the birth of a child from the state. This will help the family in the first time after the birth of the baby. To do this, a woman must contact the antenatal clinic at her place of registration or residence and submit the following documents:

1. Passport.
2. Compulsory health insurance policy.
3. A copy of the ultrasound confirming the fact of pregnancy.
4. Insurance certificate of the Pension Fund of the Russian Federation.

This way the woman will ensure constant monitoring of her health and the health of her child.

Early pregnancy or pregnancy before 12 weeks

However, in European countries pregnancy is not maintained until 12 weeks. It is believed that a child must fight for his own future. And if a woman has a miscarriage, it means that the fetus has some kind of genetic disease, for example Down syndrome, and the mother’s body itself gets rid of the embryo. Therefore, doctors in Western countries do not interfere with the process of pregnancy until the 12th week.

Russian doctors are more loyal. They are fighting for every future person in the country. If the fetus has no abnormalities, then the woman is placed in storage and treatment is prescribed. In the early stages of pregnancy, deviations may be due to placental abruption, uterine tone, or a lack of the hormone progesterone. The pregnant woman is prescribed appropriate treatment.

In general, it indicates the end of the first trimester of pregnancy. From this period, the manifestation of toxicosis decreases, and the embryo inside the woman is now called a fetus.

IVF fertilization

Every woman dreams of becoming a mother, but not everyone succeeds. Some women, for various reasons, cannot become pregnant naturally, then doctors resort to IVF fertilization. When a couple is unable to get pregnant on their own, IVF fertilization comes to the rescue

The older a woman gets, the lower the effectiveness of artificial insemination. According to statistics, IVF resulted in a long-awaited pregnancy in women, depending on age:

• up to 29 years old - 83%;
• up to 34 years old - 61%;
• up to 40 years old - 34%;
• after 40 years - 27%.

It is possible to say that IVF was successful only two weeks after the last IVF procedure. To do this, a woman takes a blood test for hCG, and the doctor, based on the test results, determines whether pregnancy has occurred or not.

Video: how IVF (in vitro fertilization) happens

Screening

To monitor the course of pregnancy and fetal development, a woman undergoes screenings - a comprehensive examination. They include ultrasound and biochemical analysis of venous blood. However, in our country this is not a mandatory procedure. Screening may be prescribed if any pathology or deviations from the norm are observed.

There are a number of cases when screening is indispensable. It is required:

• pregnant women over 35 years old, as well as if the father’s age exceeds 40 years;
• in the presence of genetic pathologies in family members;
• if you have had a previous missed pregnancy, miscarriage or premature birth;
• pregnant women who suffered any infectious disease in the first trimester;
• women who are forced to take medications that can be dangerous to the fetus and affect the development of pregnancy;
• women working in hazardous industries and/or those who have bad habits.

During the entire pregnancy, screening is carried out three times: in the first, second and third trimester:

1. The first screening is carried out between 11 and 13 weeks and includes an ultrasound and blood test.
2. The second screening is between 16 and 20 weeks. Also consists of an ultrasound and blood test.
3. The third screening is between 30 and 40 weeks. Includes ultrasound only. The doctor determines how the delivery will take place: natural or cesarean section.

Tests and diagnostic procedures common to all pregnant women

Having become pregnant, a woman should be prepared that within 9 months she will have to undergo many different tests. She will test some all the time, while others will test only once during the entire pregnancy.

When you first visit a gynecologist and register with the antenatal clinic, usually this happens before the 12th week of pregnancy, you will need to take the following tests:

• general urinalysis - helps to identify inflammatory diseases genitourinary system and kidneys;
• urine culture tank - reveals infectious diseases genitourinary system;
• general blood test - determines hemoglobin, coagulability, ESR;
• biochemical blood test - determines sugar levels, as well as disturbances in the metabolism of proteins and carbohydrates;
• blood test for group and Rh - to exclude Rh conflict with the child, as well as if complications arise for a possible blood transfusion of the mother;
• vaginal smears;
• tests for:
  • Torch infections;
  • for HIV;
  • syphilis;
  • hepatitis B and C.

All tests have been completed, the woman has been registered at the antenatal clinic and now, at every visit to the gynecologist, the woman must undergo a general blood and urine test, and her weight and blood pressure are also measured during the visit.

Table: tests and diagnostic procedures for a pregnant woman by week

Analyzes	1st trimester	2nd trimester	3rd trimester
Clinical blood test	Every visit	Every visit	Every visit
Clinical urine analysis	Every visit	Every visit	Every visit
Blood sugar test	8–10 weeks		30 weeks
Flora smear	8–10 weeks	20 weeks	38 weeks
Blood test for HIV, syphilis, hepatitis B and C	8–10 weeks		30 and 38 weeks
Blood clotting test	When registering		30 weeks
Ultrasound	10–14 weeks	20–24 weeks	32–36 weeks
Prenatal diagnosis	Double test (blood test for hCG and PAPP) 8–13 weeks	Triple test (blood test for hCG, AFP, free estriol) 16–18 weeks
Examination of the cervix for ICN		16–18 weeks
Wiggling test		from 28 weeks
CTG (cardiotocogram)			weekly from 32 weeks
Doppler study			30–32 weeks

What week should you start preparing for the maternity hospital?

A woman, having registered with the antenatal clinic, will also receive information from the doctor about the things needed in the maternity hospital and the deadline by which they need to be collected.

I have three children. I started packing my bags gradually, starting at 20 weeks. It’s not that expensive, and there’s still time to think about what’s necessary. By week 35 I had my bags ready.

In general, every woman is an individual, so everyone has a different approach to preparing things. Some people begin to prepare only after learning about pregnancy, while others, on the contrary, wait until the last minute and at 38 weeks are running around looking for the things they need.

Every time I collect it at 10-14 weeks... Don’t ask why! Oddity! And then the most entertaining thing - the belly grows and the bag grows!!! Just before the maternity hospital, my husband laughingly clarifies: have you decided to take the children and quietly leave me?! ….. Well, or: don’t you take the piano? Strange, but what about the development of a sense of beauty in a child?! ……. Like this

Shunechka

Week 39 - contractions - and I’m flying around the apartment collecting bags, I haven’t had time to wash the children’s things yet... in the end I’m already in the delivery room, and my sister is ironing the children’s things at home, they barely managed to hand them over to me in the delivery room. So it’s better, as the girl wrote above... with a piano, but calmly!

Babayko

https://sovet.kidstaff.com.ua/question-162319

The most dangerous weeks of pregnancy

During pregnancy, a woman may face such dangerous situations as miscarriage or premature birth:

1. The first one occurs at 2–3 weeks. At this time, the fertilized egg attaches to the uterine mucosa. Many women do not even realize that they are in interesting position, and their various gynecological diseases can lead to miscarriage.
2. The second dangerous period of pregnancy occurs at 8–12 weeks. During this period, the placenta is formed, and the woman intensively secretes hormones necessary for its growth and development. Insufficient hormone production can also lead to miscarriage.
3. The third dangerous period occurs at 18–22 weeks of pregnancy. During this period, increased growth of the uterus occurs. Incorrect location of the placenta, infectious diseases, weakened position of the cervix - all this in the second trimester can lead to miscarriage.
4. The fourth dangerous period of pregnancy occurs at 28–32 weeks. During this period, there is a danger of premature birth. The reasons for their occurrence may be: late gestosis, abruption or placental insufficiency. There is a high risk of fetal death.

What week is the most common time to give birth?

Women's due dates vary for a number of reasons. Thus, primiparous women give birth later than multiparous women. This occurs due to the fact that the birth canal of firstborns is not yet prepared, the cervix opens slowly, and labor occurs later.

There is also an opinion that girls are more active and are born earlier than boys.

I completely disagree with this. I gave birth to my two boys at 38 weeks, while the princess was in no hurry to get to know us. I gave birth to my daughter at 41 weeks.

In a study of 11,000 births, birth statistics were compiled by week:

• at 37 weeks, birth occurred in 5% of healthy pregnant women;
• at 38 weeks - in 13% of women;
• at 39 weeks - in 20% of women;
• at 40 weeks - in 35% of women;
• at 41 weeks - in 17% of women;
• at 42 weeks - in 10% of women.

Fetal development and woman's sensations by week

Every week of pregnancy brings something new in the woman’s feelings and the development of the fetus.
How the fetus develops every week

Table: changes in the body of a pregnant woman every week and fetal development

A week	Changes that occur every week in a pregnant woman's body
1	The egg matures and prepares for release from the ovary.
2	The egg is actively developing. By the end of the second week, ovulation occurs.
3	Fertilization of the egg. By the end of the third week, the embryo is implanted and the placenta is formed.
4	The first signs of pregnancy appear: swelling of the mammary glands, nausea, nagging pain in the lower abdomen	The embryo is actively developing. Internal organs and the nervous system are formed. The umbilical cord is formed.
5	Tests 100% confirm pregnancy. The woman begins to show signs of toxicosis, fatigue, and drowsiness.	The placenta and membrane of the fertilized egg develop. The reproductive, nervous and circulatory systems are formed. As well as the upper respiratory tract, liver and pancreas.
6	It’s time for a woman to see a doctor and register with an antenatal clinic.	The neural tube tightens and the brain begins to form, facial features develop, and arms and legs form.
7	The woman continues to suffer from toxicosis. Due to hormonal changes, the condition of the skin and hair worsens. The uterus increases in size and this leads to increased urination.	The child’s internal organs are actively developing: the heart becomes two-chambered, the lungs develop, the small intestine is formed, the esophagus and trachea develop.
8	The woman’s signs of toxicosis intensify, and weakness and fatigue also increase.	During this period, almost all important organs are formed. Then they only improve, grow and develop.
9	Toxicosis torments a pregnant woman even more, which can lead to weight loss. Swelling of the mammary glands is observed.	The embryonic stage of the baby's development ends. The child's pituitary gland and cerebellum are formed.
10	If toxicosis in a woman is accompanied by vomiting, then she loses weight. If there is no toxicosis, the woman gains 1.5–2 kg in weight.	Some of the child’s organs are already working - these are the intestines, kidneys, liver and pancreas. The baby can also move and swallow.
11	The hormonal balance returns to normal, metabolic processes intensify, and the volume of circulating blood increases.	The baby develops a grasping reflex, the formation of the sternum, diaphragm and genitals is completed. The baby's intestines begin to work, and his liver is already producing blood.
12	Pigmentation may occur, a dark line from the navel to the pubis, which will disappear after childbirth.	The child is actively developing. Able to roll over, open his mouth and move his fingers. The genitals are formed, the liver begins to produce bile.
13	The uterus increases in size and rises into the abdominal cavity.	The skeletal system is actively forming, and the respiratory system is already well formed. The thyroid gland is well developed, and the pancreas produces the first insulin.
14	A woman’s body is preparing for the role of a mother, and the desire to prepare a corner for the baby awakens.	The face already looks like a newborn. The baby's taste buds develop.
15	Toxicosis recedes, urination returns to normal, but leg cramps may begin, which may indicate a lack of calcium, magnesium or potassium.	The cerebral cortex and central nervous system are formed, glands develop internal secretion the fetus, the respiratory system develops, and taste buds are formed.
16	Due to the change hormonal levels, namely due to an increase in the hormone estrogen, which provokes swelling of the nasal mucosa, 30% of women may experience rhinitis during pregnancy.	The liver, kidneys and bladder perform their functions. Blood contains everything necessary elements: red blood cells, lymphocytes and monocytes.
17	A woman gains from 3 to 6 kg. In this regard, the load on the legs increases, which begin to swell and hurt.	The hearing organ is formed, the formation of the conduction system of the heart is completed, and the swallowing reflex develops. The skin is covered with a special fluff.
18	Weight gain provokes back and lower back pain. Vaginal discharge may appear.	The baby’s immune system and hearing organs are formed, and the heart is actively working.
19	Due to the fact that a lot of calcium is needed for the baby to fully develop, and if there is a deficiency, it is taken from the woman’s teeth, the expectant mother should pay attention to their condition. It is advisable to visit a dentist.	The brain develops, connections between the nervous system and muscles are established. The baby's respiratory system is created, which includes the lungs, bronchi and bronchioles.
20	Vaginal discharge increases. Possible development of varicose veins	The child develops subcutaneous fat tissue.
21	An enlarged uterus can cause heartburn, and a growing belly can cause back pain and stretch marks.	Endocrine glands perform their functions, the nervous system develops, and the digestive tract functions. The spleen begins to work.
22	The woman’s gait changes, swelling and varicose veins appear. Baths with herbal infusions or massage will help you cope with them.	All the baby’s internal organs work harmoniously, and the liver begins to produce a variety of enzymes.
23	A woman should begin preparing for childbirth and pay enough attention to her physical condition.	The pancreas begins to produce hormones, including the main one - insulin.
24	There is a risk of developing anemia, and therefore a woman needs to pay attention to her diet. It must be complete and contain a sufficient amount of vitamins and minerals.	All sense organs are formed. The baby begins to prepare for birth.
25	The expectant mother gains weight, the manifestation of pigmentation intensifies: the isola area darkens and the stripe from the navel to the pubis appears more clearly.	Bone marrow development is completed, but bone tissue continues to form. The fetal heart rate is 140–150 beats per minute.
26	It would be a good idea to purchase a prenatal bandage. It will help relieve stress from the spine.	The rudiments of teeth are formed, the bone apparatus is strengthened, and muscles increase.
27	Often a woman is plagued by constipation. Many people experience increased blood pressure and may also experience a feeling of heat or excessive sweating.	The baby is proportionally developed, his appearance is like that of a newborn child
28	Due to weight gain, lower back pain appears, which covers the thigh, sometimes even reaching the ankle. A lack of calcium in the expectant mother's body can trigger seizures.	The baby continues to grow and develop. The respiratory system is fully formed.
29	An increase in the weight of the expectant mother and compression of the lower pelvic vein provoke a violation of the outflow of blood from the lower part of the woman’s body. This in turn leads to varicose veins, hemorrhoids and constipation. And an enlarged uterus can cause shortness of breath and heartburn.	Blood contains all the necessary substances, it can carry oxygen, protect against infections and bleeding.
30	The high level of progesterone accumulated in the body of a pregnant woman provokes hypersensitivity and engorgement of the mammary glands.	The respiratory system is formed, now the child is training his lungs so that at birth he can breathe.
31	Women should pay attention to the regularity of bowel movements; for many, it is disrupted and accompanied by flatulence. A significantly enlarged uterus does not allow a woman to rest on her back. In this position, she becomes dizzy and ill.	The brain is actively developing. The weight of internal organs increases.
32	The baby has grown enough and now, tossing and turning in his tummy, causes inconvenience for his mother. Many pregnant women toss and turn all night, trying to find a comfortable sleeping position.	The baby's immune system is being formed. Now, when receiving immunoglobulins from the mother, the baby’s organs begin to produce antibodies, creating protection for themselves in the first months after birth.
33	Now all the woman’s thoughts are occupied by the upcoming birth. She becomes anxious and restless. Lack of calcium, as well as accumulated excess fluid in the body, provoke the appearance of seizures.	The baby has already grown enough and is quite viable. If a woman suddenly goes into premature labor, the newborn will be able to exist independently.
34	Many women experience uterine contractions, also called false contractions. The uterus of the expectant mother has increased several dozen times.	The baby is already ready to receive his first food, but for now his intestines receive only amniotic fluid, which is processed into original feces - meconium. At birth, meconium will be passed from the newborn's body.
35	A huge burden falls on a woman’s body during pregnancy. And it is not only physical, but also psychological. Women are distracted, forgetful, and find it difficult to concentrate.	The development of the adrenal glands is observed, which contain hormones responsible for water-salt and mineral metabolism.
36	The placenta gradually ages. Intensive aging of the placenta can cause fetal hypoxia ( oxygen starvation), which in turn will lead to impaired development and growth.	The child has already grown up enough and is already cramped in the womb. His movements are constrained, and pushes and turns are painful for mom.
37	The mucus plug begins to stand out. During pregnancy she played a protective role. The cervix begins to prepare for dilation.	The baby is ready to meet his mother. The nervous system continues to develop.
38	The fetus begins to move down and puts pressure on the pelvic bones. This causes pain for the woman. The woman's breasts become fuller, and her nipples become very sensitive.	The child’s muscles are in the required tone. The kid continues to wait for the meeting.
39	Pain in the back and lower back, swelling and constipation, varicose veins and heartburn continue to bother a pregnant woman.	In anticipation of the meeting, the baby moves into the mother's pelvic cavity.
40	The ideal option is childbirth. Even if they did not occur this week, the uterus has already dropped, thereby easing the condition of the pregnant woman. Now the expectant mother can breathe easier, and her actively functioning stomach eliminates the symptoms of heartburn. The descending fetus puts pressure on the genitals, and the woman experiences heaviness and pressure in the perineum.	A significantly aged placenta is no longer able to perform the functions assigned to it. This is very dangerous for the unborn baby, since a lack of oxygen leads to problems with the functioning of the brain and internal organs.
41	Ideally, the woman should have already given birth. The body is constantly preparing for this. If the woman has not done this before, then she urgently needs to start preparing her breasts for breastfeeding.	The baby is ready to be born, he doesn’t have enough room in his tummy, he can’t even move.

And now the long-awaited meeting has arrived.
The most unforgettable experience is hugging a newborn baby

As a mother of three children, I can only say good things about pregnancy. Despite the toxicosis in the early stages, I liked the feeling of nascent life. To avoid gaining too much weight, I walked to work. It took about 40 minutes to walk. Firstly, fresh air, and secondly, physical activity so necessary during pregnancy. What a joy it is when the baby moves. An incomparable feeling. I really understand women who have many children. These little people give great joy and happiness.

Video: human fetal development

What a joy it is to have a child. If a woman, having decided to become a mother, is attentive to her health and follows all the doctor’s prescriptions and recommendations, pregnancy will not cause much trouble for the expectant mother.

Pregnancy is a process in which a baby develops from two tiny parent cells. The development of the fetus by week of pregnancy is a fascinating story about what exactly happens in each week of pregnancy, how the weight and height of the fetus changes, what sensations arise in the mother as the pregnancy lengthens. In the article we will tell you about what interests every expectant mother: when the baby begins to hear her speech, when and how the weight of the fetus changes, when you can take a photo of the fetus with an ultrasound, what causes the mother’s feelings during pregnancy, and much more.

First and second weeks of pregnancy: baby? Which child?

At the moment the embryo appears, the pregnancy period is already 2 weeks. Why? Let's decide from what we will calculate the period. There are concepts of embryonic and obstetric term. The embryonic period of pregnancy is the true period from the moment of conception. Obstetric period – from the first day of the last menstruation. The obstetric period is on average 2 weeks longer than the embryonic period. During an ultrasound, the pregnant woman’s chart and sick leave will always indicate the obstetric period according to the date of the last menstruation. But from the third week of pregnancy, the development of the fetus actually begins. Below you will find a description of each week of pregnancy: how the fetus develops, what happens to the uterus, how the expectant mother’s sensations change.

3rd week of pregnancy: parents meeting

At the end of the second and beginning of the third week (on average on the 14th day of the cycle), ovulation occurs. At this moment, the woman’s egg leaves the ovary into the fallopian tube and where it meets the sperm in the next 24 hours. Of the 75-900 million sperm that enter the vagina, less than a thousand reach the cervical canal. And only one will penetrate the egg.

The sperm and egg carry half the set of chromosomes of the future person. As a result of their fusion, the first cell of a new organism with a full set of chromosomes is formed - a zygote. Chromosomes determine the baby's gender, eye color, and even character. The zygote begins to divide and move towards the uterine cavity. The journey to the uterus will take approximately 5 days, by which time the embryo will consist of approximately 100 cells. The next stage is implantation - the introduction of the embryo into the wall of the uterus.

4th week of pregnancy

The ball of cells is officially called an embryo. The size of the fruit at this stage is like a poppy seed, approximately 1.5 mm.

At the end of this week, the expectant mother notices that the expected menstruation does not begin. On this period a woman may feel the first signs of drowsiness, weakness, increased sensitivity of the mammary glands, and mood swings. A pregnancy test shows a positive result. The test detects the hCG hormone, which begins to be produced after implantation.

The embryonic period lasts up to 12 weeks. The axial organs and tissues of the baby are formed. A yolk sac with a supply of nutrients and an amniotic sac are formed; from these extraembryonic organs, the fetal membranes and chorion - the future placenta - subsequently develop. Below we will look at what happens in embryonic period every week, how the height and weight of the fetus changes and what sensations await the woman.

5th week of pregnancy

The embryo consists of three layers - the outer ectoderm, from which the ears, eyes, inner ear, and connective tissue will be formed; endoderm, from which the intestines, bladder and lungs will develop; and mesoderm is the basis for of cardio-vascular system, bones, muscles, kidneys, reproductive organs.

The anterior and posterior poles of the embryo are determined - the future head and legs. The body of the embryo is laid along the axis of symmetry - the chord. All organs will be symmetrical. Some are paired, for example, kidneys. Others grow from symmetrical buds, such as the heart and liver.

At the 5th week of pregnancy, with a hCG level of 500-1000 IU/l, a fertilized egg can be determined to be 2 mm in size, which is the size of a sesame seed. Each woman experiences this period differently, but most experience nausea, drowsiness, and odor intolerance - signs of toxicosis.

6th week of pregnancy

Now the baby is no larger than a lentil, at the beginning of the week 3 mm, and by the end - 6-7 mm. The embryo is somewhat similar to a fish and still bears little resemblance to a person. The rudiments of arms and legs appear. When the hands appear, the legs will still be in the form of rudiments. The cerebral hemispheres are formed. The small heart is pulsating and is dividing into sections.

The future placenta is formed from chorionic villi, vessels actively grow through which blood is exchanged, and accordingly everything necessary for the unborn child between mother and baby.

At this time, toxicosis may intensify, and severe weakness and vomiting may appear. Drinking enough fluids is important during these weeks of pregnancy.

7th week of pregnancy

The embryo is approximately the size of a blueberry, height 8-11 mm, weight up to 1 g. Hints of the future nose, eyes, ears and mouth appear. There is a fantastic rate of brain growth - 100,000 cells per minute! Interdigital spaces have already appeared on the handles, but the fingers are not yet separated. The umbilical cord and the uteroplacental circulatory system are formed: the baby’s breathing and nutrition comes from the mother’s blood.

It is during this period that many expectant mothers often come for their first ultrasound scan during pregnancy. At 7-8 weeks, the CTE (coccygeal-parietal size) is 10-15 mm. An ultrasound detects a heartbeat with a frequency of 100 to 190 beats per minute, which is significantly higher than that of an adult. At this time, the first photo of the gallery of fetal development is taken week by week. Without a doctor's instructions, you won't know where to look. It will be clearer later, especially on a 3D ultrasound.

While the mother has not yet noticed an enlarged abdomen, the gynecologist can already tell about an enlarged uterus. The woman experiences increased urination, which is associated with an increase in the volume of fluid in the body.

8th week of pregnancy

The baby is the size of a bean, from 15 to 40 mm, and weighs approximately 5 grams. Over the past two weeks it has grown 4 times! The contours of the face continue to develop, they become more graceful, the upper lip and tip of the nose stand out, and the formation of the eyelids begins.

At the 8th week of pregnancy, ossification of bones begins - arms, legs, skull. The structuring of the gastrointestinal tract, heart, kidneys, and bladder is completed.

Around 7-8 weeks of pregnancy, the baby begins to move, but the mother will not feel these movements in the coming months. Mom’s condition remains virtually unchanged. It may become easier due to adaptation to the condition and awareness of your new role.

9th week of pregnancy

The little man is only the size of a grape - its length is 35-45 mm, and its weight reaches 10 grams. The formation of the reproductive system occurs, and the adrenal glands are already producing hormones, including adrenaline.

The brain is rapidly developing, including the cerebellum, which is responsible for coordinating movements. Movements become more controlled. The digestive system is actively developing. The liver begins to produce new blood cells. The head occupies half the entire length of the body. Tiny fingers are getting longer.

The amount of circulating fetal DNA in the mother's blood is sufficient to perform a non-invasive prenatal test.

The mother still has signs of toxicosis. Usually at this time she turns to a gynecologist to register.

10th week of pregnancy

Do you know this fruit - kumquat? This is approximately the size of the baby now. This week it will officially be called a fetus, but for now we call it an embryo. This period is considered the end of the first critical period. Now the dangerous effect of drugs leading to developmental defects is not so significant.

A lot of events are happening these days. The webbing between the fingers disappears and the fingers separate. The bones harden. The kidneys begin to work, performing their main function - producing urine. The brain produces 250,000 neurons every minute. A diaphragm is formed between the abdominal and thoracic cavities.

My mother is experiencing symptoms of toxicosis. Due to changes in nutrition, metabolism, muscle tone and hormonal fluctuations, your figure and body movements may change. The uterus is the size of a grapefruit, but the pregnancy is not yet noticeable to others.

11th week of pregnancy

From 11 to 13 weeks, the baby undergoes a serious medical examination - ultrasound screening. The thickness of the collar space and nasal bones are determined, a study of blood vessels is carried out, and gross changes in the structure of the body are excluded. They examine the internal organs, facial structure, brain, arms and legs, and spine. Your baby is only the size of a fig, and the doctor describes the anatomy of the fetus in such detail! The head is still large relative to the body, but the proportions continue to change: the head is large, the body is small, the upper limbs are long, and the lower ones are short and bent at the knees. The rudiments of nails and teeth appear.

With the results of the ultrasound, the mother is given a biochemical blood test to check for chromosomal abnormalities and the risk of developing pregnancy complications.

The symptoms of toxicosis are replaced by new sensations: heartburn, bloating, and there may be constipation. A woman should pay more attention to her diet and fluid intake.

12th week of pregnancy

Your baby is about the size of a lime. Until 11-12 weeks, there are no reliable ultrasound differences between boys and girls. The probability of correctly determining the sex of the fetus is already above 50%. The weight of the fruit is about 20 grams, and the length is about 9 cm.

At this stage, the baby begins to actively move his arms and legs, hands, and fingers. Due to active growth, the intestines no longer fit in the tummy and begin to fold into loops. During this period, the intestines are trained: amniotic fluid passes through it, which is swallowed by the fetus. White blood cells appear in the blood - leukocytes, which have the function of protecting against infections.

Mom's weight gain by the 12th week of pregnancy is about 1-2 kg. Doctors recommend doing gymnastics for pregnant women, and swimming is recommended.

13th week of pregnancy

A pea pod is how you can describe the size of a baby in everyday measurements. Or 7-10 cm, 20-30 grams. From the 13th week the second trimester of pregnancy begins. All the main organs and systems have already been formed; the rest of the time before birth, the organs will grow and develop.

The face becomes more and more human-like. The ears move closer and closer to their place from the neck, and the eyes from the side to the center of the face. The first hairs appear. 20 baby teeth have been formed.

The head is still disproportionately large, but the body will now grow faster. The hands continue to grow, the baby can already reach his face. Often, during an ultrasound, doctors show parents how the baby puts his finger in his mouth.

During this period, the shape of the abdomen changes, and the previous clothes become tight. Those around you may notice a woman’s new emotional mood; she becomes calmer and more relaxed.

14th week of pregnancy

At week 14, the fetus grows to 13 cm and 45 grams. In boys, the prostate forms, and in girls, the ovaries descend into the pelvis. The palate is already fully formed, active reflex sucking begins. The baby imitates breathing movements in order to effectively take the first breath after birth.

The formed pancreas begins to produce the most important hormone of carbohydrate metabolism - insulin. And in the depths of the brain, the pituitary gland begins to work - the head of all organs of the endocrine system, it is he who subsequently controls all the glands of the body.

The uterus is located 10-15 cm above the pubis; the woman herself can feel its upper part. It is recommended to use special cosmetics for the skin of the abdomen.

15th week of pregnancy

The fruit is the size of an apple and weighs about 70 grams. The whole baby is covered with small vellus hair - they are on the back, shoulders, ears, and forehead. These hairs help retain heat. Then, when the baby gains enough fatty tissue, the hairs will fall off. The child makes various grimaces, winces, frowns, squints, but this does not reflect his mood at all. He changes his position all the time, actively moving. But the baby is still too small and does not hit the walls of the uterus. A unique skin pattern appears on the fingertips and special proteins appear on the red blood cells that determine the blood type.

Mom may develop pigmentation on her stomach.

16th week of pregnancy

The baby is the size of an avocado. Skeletal bones become harder, but flexible enough for the baby to pass through the birth canal. The umbilical cord contains one vein and two arteries, surrounded by a gelatinous substance that protects the vessels from pinching and makes the umbilical cord slippery for movement. In girls these days, sex cells are formed - your future grandchildren.

Weight gain during this week of pregnancy is 2-3 kg.

17th week of pregnancy

The baby's size is 12-13 cm and weighs up to 150 g, the size of a turnip. The arms and legs are commensurate with the size of the body and head. Fat begins to be deposited under the skin and sweat glands develop. The placenta provides the baby with vitamins, minerals, proteins, fats and oxygen while removing waste products.

Due to an increase in the volume of circulating blood, the mother may experience a rapid heartbeat. In this case, bring this to the attention of your doctor to see if everything is okay.

18th week of pregnancy

Your child is the size of a bell pepper and weighs 250 grams and is ready to communicate. Yes, now the baby can hear, and a loud sound can scare him. He gets used to his parents' voice, and will soon be able to recognize it from other sounds.

The fetal endocrine system is actively developing and functioning. There are so many “baby” hormones that the baby can even supply the mother’s body.

This week, mom may feel fetal movements for the first time. As long as they are mild and infrequent, don't worry if you don't hear your baby too often.

19th week of pregnancy

The height of the fetus is 25 cm, and the weight is already 250-300 grams.

The cheese-like lubricant coats your baby's skin and helps regulate body temperature. The formation of molars occurs; they are located under the rudiments of milk teeth. The head does not grow as quickly, but the limbs and body continue to grow, so the baby becomes more symmetrical.

The uterus is located 1-2 cm below the navel. Due to its intensive growth, painful sensations associated with stretching of the uterine ligaments may occur.

20th week of pregnancy

A happy child weighing 240 grams. At this stage, he is especially good at flexing and extending his arms and legs. He is becoming more and more like his parents.

Week 20 is the equator of pregnancy. The growing uterus compresses the internal organs, so the mother experiences shortness of breath and frequent urination.

During these weeks, the mother attends the next scheduled ultrasound and Doppler measurements are performed. This is a good time for a video ultrasound and regular photos of the heir.

21st week of pregnancy

The height of the fetus is 25 cm, and the weight is 400 g. Most of the nutrients come from the placenta. If amniotic fluid is swallowed, the stomach is already equipped to digest it and receive nutrients. The baby begins to feel the taste.

The mother gains more weight as the baby grows rapidly.

22nd week of pregnancy

By the end of the week the baby will be about 500 grams. The skin is no longer transparent, but remains red and wrinkled and covered with grease. Nerve endings mature and the baby becomes sensitive to touch. From 21 to 25 weeks, the brain increases 5 times - from 20 to 100 grams!

23rd week of pregnancy

Billions of brain cells will develop over the next few weeks. Their job is to monitor all of your baby's movements, senses, and basic life functions such as breathing.

The lungs begin to produce a substance that allows the lungs to inflate and fill with air after birth, and the fetus begins to “breathe.” The frequency of respiratory movements is 50-60 per minute.

The height of the uterine fundus is 4 cm above the navel. The uterus grows, which can cause discomfort in the spine and joints, so a special bandage may be required.

24th week of pregnancy

The baby is still small, his weight is 600 g, and his height is about 33 cm. The child actively reacts when addressed to him. The inner ear is already fully formed ( vestibular apparatus), he began to understand where is up and where is down, movements in the uterine cavity become more meaningful.

Mom gains about 500 grams per week. Swelling of the feet may occur, so it is important to choose comfortable shoes and rest your feet.

25th week of pregnancy

The height of the fetus is 30-32 cm, weight is 750 grams. Meconium forms in the large intestine - the baby's first stool, which will be completely passed within a few days after birth. The osteoarticular system is actively developing, bones are strengthening.

The mother may experience signs of anemia (anemia) developing due to iron deficiency. Fatigue, pallor, fatigue and tachycardia are reasons to consult a therapist and take blood tests for anemia.

26th week of pregnancy

Height 34 cm, weight 900 grams.

The lungs are actively developing, they are filled with a special substance that will not allow the lungs to stick together after the first breath.

The child has clearly defined periods of sleep and wakefulness. Mom feels his activity by movement in her stomach. If you are lucky, your sleep and activity periods will coincide with your baby's.

27th week of pregnancy

The fetal body weight is already about a kilogram, and its height is 34 cm. Growth hormone begins to be produced in the pituitary gland. And the thyroid gland contains hormones that regulate metabolism.

Due to involuntary contractions of the diaphragm, the mother may feel hiccup-like movements of the baby. In adults, such movements are accompanied by the closure of the vocal cords, which is why the characteristic “hiccup” sound occurs, but in a baby before birth, this space is filled with liquid, so this “hiccup” is silent.

New sensations may occur in the legs - tingling, goosebumps or even cramps. This is a reason to consult a doctor for further examination and treatment.

28th week of pregnancy

Now your baby is beginning to close and open his eyes, which until this moment were not completely closed. The iris of the eyes acquired color due to pigment, although this coloring is not final. Children's eye color may change until they are one year old.

At week 28, in case of multiple pregnancy, the mother receives a “sick leave”. The weight gain by this time is 7-9 kg. At this time, Rh-negative mothers are given immunoglobulin.

29th week of pregnancy

The child is 36-37 cm long, weighs approximately 1300 grams and is becoming stronger and more active. We can say that he shows character. A child reacts differently to different foods, sounds, and light.

A woman suffers from heartburn and heaviness after eating. There may be frequent urination or even false urges.

30th pregnancy

In the coming weeks, your baby will actively gain weight. Adipose tissue will perform the function of thermoregulation after birth, provide energy, and protect organs. The baby's movements will become less active, which is associated with an increase in his size. But if you do not feel any shocks as usual, be sure to tell your doctor. Pregnant women may feel breast swelling and notice the release of colostrum.

At this time, a certificate of incapacity for work is issued for a singleton pregnancy.

From 28-30 weeks of pregnancy, regular CTG (cardiotocography) begins to assess the condition of the fetus. CTG evaluates fetal heartbeat, uterine tone and motor activity.

31st week of pregnancy

Before birth, the little man will be in the fetal position, because otherwise he will no longer fit in the uterine cavity, his weight is 1600 g, and his height is already 40 cm.

These days, an important event occurs in male fetuses - the testicles on the way to the scrotum. In girls, the clitoris is almost formed.

Weekly weight gain - 300-400 grams. During these periods, swelling may appear and blood pressure may increase, which can be a symptom of a serious complication - preeclampsia. Therefore, the expectant mother should be as attentive as possible to any changes in well-being.

At 30-32 weeks, an ultrasound of the third trimester is performed with Doppler measurements - assessment of blood flow.

32nd week of pregnancy

This important week, another critical period has passed. Babies born at this stage are healthy and fully functional. By this week, all major organs are functioning fully, except for the lungs, which need a little more time to fully mature.

The expectant mother may experience pain in the joints and symphysis pubis. These phenomena can be alleviated by wearing a bandage and swimming.

33rd week of pregnancy

It is becoming increasingly difficult for the baby to move; he is already 44 cm and weighs about 2 kg. Many children like to live at their mother's rhythm: sounds, food and walks can influence the child's activity.

The height of the uterine fundus is 34 cm from the level of the pubis. It becomes more difficult for mom to walk or exercise a lot and needs a break.

34th week of pregnancy

Within a few weeks, your boy or girls begin to prepare to meet their parents. The original white lubricant that covers the skin begins to thicken, accumulating in the armpit and groin folds, behind the ears. At the time of the newborn's first toilet, the lubricant will be removed. Height 47 cm, weight 2200-2300 g.

Pregnant women begin to feel false contractions - the muscles are preparing for the birth process.

35th week of pregnancy

The fetus is preparing for birth, finally taking the correct position, upside down. This is the case for approximately 97% of children. The remaining 3% may occupy a position with the pelvis down or even transverse. Fetal height is 47-48 cm, weight is 2300-2500 g.

Almost all expectant mothers experience shortness of breath at this stage.

36th week of pregnancy

The baby continues to store fat, which is vital after birth for energy and heat retention. The sucking muscles are ready to work: after birth, the baby will be hungry and will ask to be fed for the first time.

The height of the uterine fundus is 36 cm. Hormonal changes in the woman’s body begin to prepare for childbirth - oxytocin and prostaglandins are produced.

37th week of pregnancy

The movements of his fingers become more coordinated, and soon he will be able to grab your finger. The accumulation of subcutaneous fat continues, its volume is approximately 15% of the baby's weight. Height 48-49 cm, weight 2600-2800 g. The vellus hair covering the body gradually disappears.

A pregnant woman feels the harbingers of labor - prolapse of the uterine fundus, a decrease in the volume of the abdomen, loosening of stools, intensification of contractions, and the passage of a mucous plug.

38-40 weeks of pregnancy

In obstetrics textbooks, 38 weeks was the term for full-term pregnancy. If your baby is born right now, it will be a full-term pregnancy, and the baby will not have any risk factors associated with birth ahead of schedule. All further events are aimed at preparing for childbirth.

The passage of a mucus plug should be distinguished from the leakage of amniotic fluid. If there is too much discharge, consult your doctor for a special test.

In most cases, the baby's head drops into the pelvis at 38-39 weeks, this is called cephalic presentation. If the child lies straight with his head down, this is called a longitudinal position, if a little at an angle, then it is oblique. There is also the concept of fetal position: I position means that the back is turned towards the left uterine wall, and II - towards the right. An ultrasound will tell you how the fetus is positioned.

At birth, doctors assess the child’s condition using several parameters: activity, muscle tone, heartbeat, breathing, skin color, reflex reactions. The more points, the healthier your baby was born.

We have now completed our journey through 40 weeks of fetal development during pregnancy. The most important thing is to be attentive to yourself and the words of your doctor, the orders of tests and ultrasounds, pay attention to all the sensations and enjoy pregnancy and future motherhood.

In this article:

Every pregnancy is the same for a woman, but feels different. This is due to her state of health and emotional and psychological state, social conditions of stay and the characteristics of the development of the fetus. Each stage of pregnancy is characterized by certain changes in the development of the fetus in the womb. What changes are we talking about, how the child grows and develops throughout pregnancy - we will talk about this in this article.

Pregnancy is an interesting and difficult period in a woman’s life. At this time, the birth and development of a new life occurs in her, her body experiences a heavy load, which gradually increases with each month of pregnancy. A pregnant woman experiences physiological and psycho-emotional changes, and her tastes and preferences may also change. All this is closely related to the stages of intrauterine development of the fetus, which grows, develops and is actively preparing for its birth.

Fetal development: stages and features

In the womb, a child develops over 9 months, or 280 days. The process of fetal development does not occur chaotically, but according to an algorithm written by nature itself and provided for by the peculiarities of human anatomy. Development of all organs and systems of the fetus occurs in a strict order and within a certain period of time.

Medicine divides pregnancy into three important stages - trimesters, each of which is characterized by the growth and development of certain systems/organs in the body of the unborn child. All stages are also divided into weeks, since the condition of the fetus changes weekly. We will look at the features of each trimester.

From one cell, trillions of new cells are formed in 38 weeks. There are more than 200 types of them, and they are biological building materials necessary for the growth and development of a child in the womb, his birth and full life on the ground.

I trimester

In the first trimester, a woman exhibits the first signs of pregnancy, when the process of fertilization of the egg occurs, its movement and fixation in the uterine cavity. During this period, the formation of the vital systems of the unborn child occurs. This trimester is considered very important for the fetus and mother, so a woman needs to take care of herself and take care of the health of her unborn baby.

According to obstetric dates
During gestation, fetal development in the trimesters can occur differently in different women. This is due to many factors - hereditary, social, physiological, psychological and other circumstances that can affect the health of the mother, the course of pregnancy and the development of the fetus.

This is the period when a woman may suffer from early toxicosis, she may feel drowsiness, general malaise, dizziness, etc. What changes the fetus undergoes in the first trimester during its development can be seen in Table 1 below.

Table 1

A week	Fetal development
1	Development of the egg, ovulation, fertilization, birth of the blastocyst.
2	The movement of the blastocyst into the uterine cavity, where it will gain a foothold and continue its development.
3	The embryo takes on the shape characteristic of a human fetus. Nerve cells form the neural tube - the basis of the future spinal cord and brain of the embryo. The heart is formed, which until this moment resembled a clot of muscle cells. The size of the embryo's heart does not exceed the size of a poppy seed. One cell suddenly contracts, setting all the heart cells in motion through a chain reaction. The embryo's heart beats 20-25 times per minute and is necessary for the embryo, since without it the complete and correct distribution of oxygen and food is impossible. Blood cells are still primitive, but with each heartbeat they circulate through the thinnest (thinner than a hair) blood vessels, delivering the necessary building material and oxygen to each cell of the embryo.
4	The period when a woman can feel pregnant due to changes in her hormonal system. The embryo is no larger than a bean, but every day it grows by 1 mm. Two black dots appear in the area of ​​his head - these are future eyes. The embryo’s heart is still single-chambered and miniature, but it already beats 80 times per minute, accelerating the pace with each new day. “Kidneys” appear on the body of the embryo; in the future, arms and legs will form from them. From the neural tube of the embryo, areas of the spinal cord and brain - the future central nervous system - are formed. The tissue growing from four sides forms the face. Her top part grows down to form an area for the formation of the nose and chin. The cheeks are formed by tissue on both sides, forming the upper lip. Its connection is called the “philtrum”, and it is preserved - it can be seen on the face of an adult. Improper fusion of this tissue contributes to the formation of a defect known as a “cleft lip.” After birth, a baby with such a defect will need the help of a surgeon. The human embryo is not much different from the embryo of any other animal. Only 1.5% of genes indicate that this is a human embryo.
5	The first heartbeats of the embryo begin to be heard. Its size is only 3 mm, but it already shows signs of the formation of the lungs, heart and thyroid gland.
6	The formation of the spine, upper/lower limbs and two hemispheres of the brain occurs, and the intestines are formed. The embryo stretches, its length is 20 mm, and its body takes on the appearance of a human embryo. The eyes are formed from black dots; they are widely spaced and not yet equipped with eyelashes. Head size still dominates relative to body size. At the time of birth, the baby's head will make up almost ¼ of his body, since the remaining parts will not be able to keep up with the growth of the head.
7	The organs of vision develop, the organs of hearing are formed (on ultrasound, the appearance of auditory elevations, eye sockets, and nasal folds is observed). An ultrasound can already clearly determine the presence of interdigital spaces; the formation of future fingers of the lower/upper extremities is taking place. The length of the embryo is 6 mm.
8	There is active growth of the embryo, formation of facial features, the nose and ears are clearly visible, and the neck is visible. It can already be called a fruit, and in appearance it looks more and more like a person. This important stage in the life of the fetus. Previously, he received nutrients through the yolk sac, a floating ball connected to the umbilical cord. Unlike a chicken yolk, the human yolk sac contains no food reserves; in the first days of pregnancy, it produces blood cells necessary to nourish the embryo. At this stage, it is unable to provide the fetus with the required amount of food, so the placenta becomes the source of nutrition for the fetus. It is connected to the umbilical cord and attached to the wall of the uterus. The placenta is a complex system that supports the intrauterine life of the fetus, consisting of an extensive network of the finest blood vessels. They are attached to the wall of the uterus and with their help the fetus, through the umbilical cord, draws from the mother’s body all the useful substances it needs: water, oxygen, proteins, etc. The fetus also excretes its waste products through the placenta.
9	At the beginning of the week, the length of the fetus is from 15 to 20 mm, the weight is 3-4 g, and at the end of the week these parameters almost double. The placenta controls the pregnancy process by producing the necessary hormones in the mother's body. The placenta acts as a filter, preventing harmful substances from reaching the fetus, but it is also unable to cope with some types of them. For example, alcohol, smoking products and many medications easily penetrate through the placenta to the fetus. In most cases, the mother's body tells her which foods her unborn child needs and which are dangerous for him. The active development of the nervous system of the embryo is observed when the body of the previously immobilized fetus begins to twitch as a result of the occurrence of nerve impulses and reflex convulsions that are not yet controlled by the brain. Movement of the fetus is necessary to stimulate muscle growth and strengthen ligaments. The brain is not yet able to control the work of the heart, which beats automatically. Its maximum speed is 157 beats per minute.
10	The brain begins to control all vital systems of the fetal body, slowing down its heartbeat. He also now controls the movement of the upper/lower limbs. The development of the sucking reflex is noted.
11	In the period from 6 to 11 weeks, the embryo undergoes important metamorphoses, its body increases almost 5 times. At the same time, the formation of more than 200 types of different cells occurs: nerve, muscle, liver, kidneys, stomach and other cells that make up the human body. All parts of the body characteristic of a person are formed. Embryo growth – 7 cm. The fetal central nervous system continues to develop, forming its response to touch and breathing.
12	The size of the embryo is no larger than the mother's fist, but it is already more adapted to the environment in which it is located and less sensitive to various stimuli. The risk of his premature birth is reduced. The skeletal system is strengthened, and all systems and organs of the fetus further develop.

All characteristic features of the human body (muscles, ribs, organs, heart, etc.) appear in the fetus during 9 weeks of the first trimester of intrauterine development.

For the development and health of the unborn baby, the first trimester is the most difficult and dangerous. Any a malfunction in the mother’s body can affect the intrauterine development of the fetus. The 3rd and 4th weeks of pregnancy are considered the most critical - during this period the process of implantation of the fertilized egg in the uterine cavity and the formation of the central nervous system of the future fetus occurs. A common cold, infection, exacerbation of a chronic disease, nervous breakdown, stress, excessive physical or psychological stress - all this can cause a woman’s hormonal system to malfunction and provoke a miscarriage.

From the last week of the first trimester, the fetus is able to distinguish some sounds. From now on, every week he will hear better, react more actively to the touch of hands on his stomach, to his mother’s voice. In the second trimester, gynecologists and psychologists recommend that pregnant women talk to their unborn child, listen to calm and pleasant music, and the sounds of nature. It is believed that the baby in the mother’s tummy hears everything and feels her mood, feels the attitude towards herself both from the mother and from those people who surround her.

II trimester

The second trimester covers the period from 13 to 27 weeks of pregnancy. In most pregnant women, toxicosis has passed by this time, the size of the tummy still allows you to move freely and wear ordinary clothes, which will soon have to be changed to dresses and sundresses for pregnant women. A woman’s well-being in the second trimester usually does not cause concern to the doctor if the pregnancy is not burdened by any developmental pathology. From 20 or 22 weeks of pregnancy, some women are advised to wear a maternity bandage to help support
growing belly, reduce pain in the back and hip joints.

By the beginning of the second trimester, the baby in the mother’s womb weighs on average no more than 30 g, and its height is about 10 cm. By the beginning of the third trimester (at 27 weeks), the fetus’s growth will be almost 35 cm, and it will weigh about 1.2 kg. The fetal skeleton is already quite well formed, so in the second trimester its brain and muscular system will actively develop. There is high mobility of the baby in the mother's womb, and between 18 and 22 weeks a woman can clearly feel the first movements and tremors of her unborn child. From Table 2 you can see what changes occur in the fetus’s body during the second trimester.

table 2

A week	Fetal development
13	The gender of the unborn child is still difficult to determine, but a competent ultrasound diagnostician will be able to recognize it. In boys and girls up to the 13th week, a bulge is formed instead of the genital organs - the angle of inclination at which this bulge is located helps the doctor to reveal the secret of the embryo’s gender. The gender can be more clearly recognized at the 15th week of pregnancy, but the formation of the genital organs in the embryo has already begun. The formation of baby teeth and the development of muscles that provide the sucking reflex are also noted. The baby is already able to move his lips. In boys, the genital organ is clearly visible on an ultrasound; their body begins to produce testosterone (male hormone), the formation of the prostate gland (for boys) or the formation of an egg (for girls) begins. The first hairs appear on the skin of the fetus (just above the eyes and above the lip). A unique pattern is “drawn” on the skin of the fingers of the unborn child.
14	The formation of sexual characteristics and intestines continues (with the presence of villi on its mucosa). Men's testicles are already capable of producing testosterone, and women's ovaries are already capable of producing eggs. The pancreas begins to produce the hormone insulin, and processes take place in the liver and spleen in which the blood cells of the unborn baby are formed.
15	The first layer of hair appears on the fetal body - fluff. The baby makes his first attempts to “breathe” on his own: the embryo breathes amniotic fluid. Now his gallbladder is starting to function. This week, a woman who has had previous pregnancies may feel fetal movements for the first time. The weight of the unborn baby is already 130-160 g, his height is 12-14 cm.
16	Ossification of the skull and strengthening of the fetal muscular system are observed. There is an increase in his motor activity (the woman may not yet feel the movements and shocks of the fetus). The sex of the unborn child is already easily determined by ultrasound. Changes occur in the proportion of the fetal body - the size of the head decreases, its lower/upper limbs lengthen, the fingers/toes separate from each other, and nail growth begins. The arms develop faster than the legs, perhaps because they act as important sensory organs and develop at the same time as other organs. The distance between the eyes has decreased, giving the baby's face a human appearance. The central nervous system is functioning, it has expanded and controls all parts of the fetal body, the movements of which have become more diverse. The muscles acquired the necessary flexibility, the baby’s movements in the womb became softer and smoother. The brain completely controls the baby’s body, whose heart no longer beats spontaneously and convulsively - its work is controlled by the brain. The heart makes no more than 140-150 beats per minute. The weight of the fetus is 180 g, and its height is 14-16 cm.
17	The formation of the placenta is completed. The baby in the womb begins not only to hear, but also to distinguish the noises/sounds that surround him. His nervous system improves, he becomes sensitive to touch, sounds, light. The fetus is too mobile, makes many complex movements and maneuvers, trying to find a comfortable position. The fetus's joints bend easily, opening up the space inside the mother's womb in a new way. By swimming and maneuvering, the baby learns to maintain balance and coordination. In the womb, the future person develops the ability to control the position and behavior of his own body in space. The fetus is in the process of forming subcutaneous fat, which participates in the body’s heat exchange processes.
18	This week marks the end of the formation of the child’s immune system. His digestive system is already formed and developed so much that it is ready to function. The baby makes swallowing movements, swallowing the amniotic fluid in which it swims. The kidneys and digestive organs are already working - some of the undigested particles will be deposited in the intestines, the remaining processed products will be excreted in the form of urine into the amniotic fluid. Some babies can already open their eyes at 18 weeks, while others will only be able to do this at 24 weeks. This is how the blink reflex develops. The baby gets to know himself and environment, actively moving. He feels himself with his fingers, touches the walls of the uterus, pushes off with his legs, jumps and turns over. He needs these skills because they are a kind of training before birth and passage through the birth canal. The grasping reflex develops well, although its significance is unclear: it is hardly useful for the survival of a newborn.
19	The movements of the fetus are more conscious, since the connection between the muscular and nervous systems is almost completely formed. A woman may first feel fetal movement at the end of the 18th or early 19th week. The baby has grown to 18 cm, his body is covered with soft hairs that will disappear by the time he is born. Molars are formed. They will begin to grow in the child when his baby teeth are replaced with permanent ones. The fetus receives sugar and water from the mother's amniotic fluid; a small portion of hydrochloric acid and some digestive enzymes are already present in its stomach. Nutrients enter his body through “breathing” and through the placenta. He receives some of them by swallowing amniotic fluid.
20	This week, the fetal body reaches the proportions that are characteristic of babies, the ratio of its head to the rest of the body is evened out. Since its fat layer is not yet fully formed, the fetal body appears thin, but the baby is active and feels normal. He is halfway through his birth. His height is already 19 cm, body weight is 300 g.
21	The baby grows and gains weight, accumulates subcutaneous fat, and his mother often begins to feel hungry. A layer of special lubricant is formed on the baby’s body, protecting its skin from the effects of amniotic fluid. This week his body weight reaches 350 g, and his height increases by 5-6 cm.
22	There is high motor activity of the fetus: the baby can change its position in the mother’s womb several times within one day. He eats, sleeps, moves - continues to explore himself and the space around him, gain weight and grow. The baby sucks his finger and can already turn his head to the side.
23	The weight of the fetus can reach 500 g. Its heart sounds are well audible with an obstetric stethoscope. Twitching of a baby's eyelids, which are visible on an ultrasound, indicates that his brain is functioning correctly. The baby may be more awake if the mother is on the move, and when she is nervous, she behaves restlessly. The baby's hair begins to darken because his body has already begun to produce a special pigment. If the baby is born prematurely, he already has a chance to live, as well as the risk of problems with brain functions.
24	The child is still active, but his growth slows down slightly at around 30 cm, and his body weight begins to increase and reaches 600-700 g. The baby opens his eyes for the first time and is able to distinguish daylight from the darkness of the night. His eyebrows and eyelashes are already beginning to appear, and his face takes on the features of a newborn baby. His lungs are developing well and he is trying to “breathe.” A baby born at 24 weeks has every chance of survival. At this stage, a woman needs to rest more and receive only positive emotions, so as not to provoke premature birth. In case of premature birth, the baby has a chance to survive thanks to modern equipment and the experience of neonatologists.
25	All the baby’s organs and systems are already functioning and at the same time continue to develop further. His heartbeat can be heard without a stethoscope by placing his ear against a pregnant woman's belly. The child’s skeleton becomes stronger, and the baby’s kicks in the mother’s stomach are more noticeable to her.
26	The baby's lungs can barely cope with the task of supplying oxygen to his organs. With a lack of oxygen, the baby freezes, trying to move less, so the mother needs to walk more in the fresh air, not smoke, and ventilate the room more often. Almost half of children born before 26 weeks have brain defects and problems in development and learning. Starting from this week of pregnancy, the baby is actively developing all the senses: eyes, ears, taste buds on the tongue. The child learns to recognize the signals sent by the impulses of his central nervous system.
27	Hair begins to disappear from the child's skin. The proportions of his body correspond to the proportions of a newborn baby, but the total mass is still not enough. His endocrine system begins to function, producing growth hormone. The baby's respiratory muscles develop. Its height is 32-35 cm, body weight reaches 1000 g. If a mother has a premature birth, the baby has every chance to survive and grow up to be a healthy, full-fledged person.

The second trimester is a period in which the active development of all systems/organs of the fetus occurs, the baby himself also grows and gains weight. He begins to actively move in his mother’s stomach and make himself known. It has its own wake and sleep patterns. He hears almost all sounds happening around him, distinguishes between darkness and light.

To a woman staying in the second trimester of pregnancy, you need to walk outside more often, ventilate your room, and eat more vegetables and fruits. She should diligently maintain personal hygiene, not neglect morning exercises for pregnant women, try not to get nervous and not take negative events to heart.

During this period, a woman is recommended to enroll in a course for a young mother, where she will learn about the features of pregnancy in the last trimester, about correct behavior mothers during childbirth and caring for the child in the first days after birth. She should also not forget to visit her gynecologist and inform him about all the changes that occur in her body.

III trimester

The last trimester for the expectant mother will not be the easiest, since her tummy has already grown quite enough. It becomes difficult for her to move, sit up, bend over, or roll over on her side in bed. It is impossible to sleep or rest on your back due to difficulty breathing and a feeling of constriction in the internal organs. Many women are afraid of the onset of labor and in the last trimester they begin to get nervous - these experiences can lead them to stress. At this time, advice and reassurance from those women who have already successfully completed childbirth is important for a pregnant woman.

As for the baby, he feels great. All his organs are already formed, he breathes on his own, hears perfectly, and is able to distinguish tastes. The baby actively kicks its legs, rolls over, and spins in all directions in the mother’s womb. Its head is already beginning to be covered with hairs, its body is covered with lubricant, which will make it easier for it to pass through the birth canal. The fetus is preparing for release, because it will soon be born. What changes occur with the baby in the third trimester of the mother’s pregnancy can be seen in Table 3.

Table 3

A week	Fetal development
28	The baby's weight is from 1000 to 1300 g, his body length is from 35 to 40 cm. The baby not only hears sounds, but also reacts to them, showing mom with pushes what he likes and doesn’t like.
29	The baby's kidneys begin to function, releasing up to 500 mg of urine per day. The adrenal glands produce androgen-like substances, and the baby’s circulatory system produces red blood cells. The baby is actively moving inside the uterus, where it becomes cramped. He gradually turns over, taking a position in which it will be easier for him to pass the birth canal. The fat layer allows the baby’s body to independently solve the problem of body thermoregulation. His skeleton has become stronger, but the bones of the skull have not yet fused completely - this feature will allow his head to squeeze through the birth canal at the time of birth.
30	The baby begins to rapidly gain weight, his height reaches 35-37 cm with a body weight of 1000 to 1400 g. His brain has reached the stage of development when the baby is already able to analyze and remember some information. At this stage, the baby’s teeth are covered with a layer of enamel. His body is cleansed of a special lubricant that protects his skin from the effects of amniotic fluid. The baby swallows this liquid, and his digestive system processes the contents of the stomach. The undigested particles will form the newborn's first stool, meconium. At the end of the 8th month, the baby’s body weight reaches 1500 g, his height ranges from 37 to 40 cm.
31	The baby continues to practice “ breathing exercises”, preparing for her first breath outside the womb. His eyes are often open, he squints in response to bright light. All newborns have blue eyes; only a few weeks after birth their color will begin to change. The pancreas continues to develop, the liver grows, and muscle mass and the volume of blood in the child’s body. The baby grows stronger, his skin becomes thicker, acquires elasticity and a characteristic bright pink hue, since there is already the necessary fat layer underneath. There is not enough subcutaneous fat yet, so a network of capillaries and vessels is visible under the skin. The height of the fetus reaches 40 cm with a body weight of about 1600 g.
32	Premature birth is no longer scary for the baby: he will be born with a body weight of 1500 to 2000 g and will be quite viable. True, his lungs are not yet well developed, and many of the reflexes he needs to survive are missing. The baby's face is cleared of wrinkles, smoothed out, and hairs grow on the head. He quickly gains body weight due to the production of immunoglobulins. During this period, some babies begin to gradually turn head down - this is the position the fetus should take before labor begins. The baby moves more, disturbing the mother and causing her some inconvenience. To calm him down, a pregnant woman needs to lie down. A protruding navel should not bother the mother: this is the result of pressure and a large load on the mother’s body. After childbirth, the navel will take its previous appearance. The child’s body weight at 32 weeks is 2000 g, height is from 40 to 42 cm.
33	At week 33, a woman is usually prescribed an ultrasound to determine how developed the fetus is, whether its development corresponds to the gestational age, and whether there are any pathologies in development. The baby’s brain is already formed, the number of neurons increases, expanding nerve connections. This week, the heart begins to gain weight, and the subcutaneous fat layer grows. The baby needs more nutrients, and he persistently demands them from his mother.
34	· The sucking reflex is developed - the child sucks his thumb, training to suck on the mother's breast. · His skeleton is getting stronger, and his body needs everything large quantity calcium. The baby moves a lot: the uterus is already cramped for him, he tries to find a comfortable position, turns over and pushes. · The lungs are ready to receive oxygen, but are not yet 100% able to function independently and fully. · The baby weighs up to 2400 g, and his body weight is 40-45 cm.
35	· The baby’s skin acquires the required color and texture, is cleared of grease, and becomes less transparent due to the accumulation of subcutaneous fat. The fluff on the baby’s body is no longer noticeable and has almost disappeared. · The development of the adrenal glands continues, and growth of the nail plates is observed. · The baby's ears are already fully deployed and correctly positioned. · There is already some original feces in the intestines of the fetus - meconium, which will be the baby's first bowel movement after birth. · The baby weighs from 2000 to 2600 g, its body length can vary from 40 to 45 cm.
36	The baby's skin is smooth, small amounts of vellus hair may remain on his back and shoulders, but it will disappear in the first days after the baby is born. The presence of a sucking reflex indicates that the baby is ready to feed at the mother's breast. A baby's fully formed heart beats steadily, but there is still a small hole between the atria. When the baby takes his first breath outside the womb, it will close. Usually this week the baby is already positioned correctly - head down. He spins inside his mother’s belly, twists his legs and pushes, but by the time of birth he must take the correct position. The baby’s body is rounded, his nervous, immune and endocrine systems continue to improve. In general, the baby is almost ready for birth. Its weight at this stage of development ranges from 2500 to 3000 g, height – from 43 to 47 cm.
37	The child’s reproductive system is established, the ovaries (in girls) and testicles (in boys) function and produce the necessary hormones. The baby’s body is covered with vernix, the accumulation of subcutaneous fat continues: on average, its increase per day is about 30 g per day. His skeleton has become stronger, the cartilage has become harder and denser, and the ligaments are stronger. The baby continues training in independent breathing: after birth, he will have to inhale air for the first time, and not amniotic fluid.
38	At 38 weeks the baby is fully viable. A child born at this stage may have some difficulty breathing, but overall he is absolutely healthy. If he is born this week, he will need medical attention and medication to help him breathe properly. Its body weight is from 2700 to 3200 kg, its height can reach 45 cm.
39	· All the baby’s organs are developed, all systems function normally. If there are any minor deficiencies, even with premature birth they can be easily eliminated. This week, the child’s body completes the construction of its own body, and the brain completely controls this process and the functionality of each system. The baby's hair on the head can grow by this time from 1-3 to 7-9 cm. It weighs more than 3000 g and its body length is almost 50 cm.
40	· This last week of pregnancy for the baby proceeds without any special changes. He is ready for childbirth, for his first breath and meeting his mother. He tries to take the correct position (head down) and waits for labor to begin. · The baby’s bones at the time of birth are not yet ossified and soft: this feature will help him pass the birth canal more easily. A large amount of norepinephrine and adrenaline can be found in his blood. These substances will support his body during childbirth, if this process drags on and the baby experiences oxygen starvation. · There is a slight increase in the level of sugar in his blood and an increase in heart rate. All this indicates the proximity of childbirth. The child's body length is last week pregnancy can range from 45 to 54 cm, body weight also varies between 3200-4100 g. · By the end of the week, the baby will turn his head down, press his knees to his body in readiness to leave the place where he has been warm, cozy, nourished and calm for all 9 months. · Intrauterine development of the fetus is now complete.

Pregnancy is a complex physiological process that occurs in a woman’s body, during which the development of a fetus from an egg occurs, ending with the birth of a new person.

Very often during a woman’s pregnancy, all the attention of her loved ones is focused on her. Everyone tries to help her with something, fulfill her desire, protect her from worries and illnesses. The main thing is for loved ones to understand that the health and well-being of the mother determines the health and life of the unborn baby.

Nature itself will cope with what is entrusted to it: the child will grow and develop in the mother’s womb. The task of a pregnant woman and her environment is not to harm the child even before he is born. And then, after 9 months, to the delight of all family members, a strong and healthy baby will be born.

The duration of pregnancy is 40 weeks. The process of fetal development is divided into weeks, months, and trimesters. For a more complete picture of bearing a child, a woman can read the description below.

Fetal development by week of pregnancy: 1st trimester 1-13 weeks of pregnancy

Obstetric and embryonic periods differ:

The beginning of the 9-month period is the time during which the fusion of male and female cells occurs, an embryo is formed, and internal organs and systems begin to develop.

1 Week

It is characterized by the process of the birth of a new life, the preparation of the cavity of the reproductive organ for the attachment of the embryo.

Happens:

1. Fusion of egg and sperm.
2. The beginning of the active process of cell division, the formation of a blastocyte - a hollow ball created from the resulting membranes.
3. Laying down genetic characteristics.
4. Starting the process of producing human chorionic gonadotropin, a pregnancy hormone, the concentration of which allows you to establish conception using test strips.
5. Development of a new layer of epithelium, preparation of the reproductive organ to receive an embryo.

In the 1st week, the expectant mother cannot notice signs of pregnancy and has no idea that conception has occurred.

2nd week

The fertilized egg attaches to the uterine cavity. An embryo is formed that receives nutrients from the mother's body. During ultrasound diagnostics, a specialist reliably diagnoses pregnancy.

Child development:

1. The fetus, which has reached a size of 2 mm, adheres to the reproductive organ.
2. A protective shell appears surrounding the embryo.
3. The process of formation of the brain, spinal cord, and circulatory system begins.

For a woman:

• Sudden mood swings occur, and a sudden onset of migraine may occur.
• Taste preferences change. An aversion to certain smells appears.
• Progesterone is intensively produced, leading to increased sensitivity and changes in the color of nipple halos.
• Periodically, spasms appear in the lower abdomen, clear, brown discharge from the vagina, without blood. This process accompanies the rupture of the follicle.

3rd week

There is a danger of fetal rejection caused by the rejection of a foreign body by leukocytes. Early toxicosis may occur due to the opposition of the body's protective bodies to the proteins of the embryo. Fruit size 2.5 mm.

Child development:

1. The circulatory system, brain and spinal cord are actively being formed.
2. The rudiments of the respiratory system appear. The facial features of the future baby are determined.
3. Establishes a connection between the child and the mother's body. The placenta appears.
4. A protective protein will be actively produced, designed to protect the fetus from the aggressive effects of the mother’s immune system.

The expectant mother is worried about:

• Sudden mood swings caused by hormonal imbalance.
• A constant feeling of drowsiness that does not go away after proper rest.
• 70% of women experience spotting from the genitals caused by embryo implantation, which is mistaken for the onset of menstrual bleeding.

4th week

Official confirmation of pregnancy by a doctor after no monthly bleeding.

In addition to the main symptom, the young mother feels:

• The first symptoms of toxicosis.
• Sudden mood swings.
• Changes in taste preferences. Intolerance to any odors, even faintly perceptible ones.
• Very thirsty.
• Constant lack of sleep.

The baby has at this stage happens:

1. Formation of germ layers: endoderm - the basis of future internal organs; ectoderm - soil for the development of the nervous system; mesoderm - the layer responsible for the cat's tissues and skeleton.
2. Development and formation of the respiratory, digestive system, brain bladders.
3. The appearance of a pulsating tube, which later degenerates into the heart muscle.
4. The emergence of limb buds.

5th week

It is characterized by the appearance of obvious signs of pregnancy, preparing the body to bear a baby. Test strips and an examination by a gynecologist will diagnose conception with 100% certainty.

Child characteristics:

1. The embryo reaches a size of 4-7 cm in length, 3.5 g. weight. It has a cylindrical shape, with the rudiments of limbs and fingers.
2. The first blood vessels are formed, and on the 22nd day from the moment of fertilization the heart contracts for the first time.
3. The foundations of the kidneys and abdominal organs are laid.
4. The fetus is separated from the chorion. The cells responsible for the growth of the genital organs appear in the yolk sac.

At the end of the first month of pregnancy, the young mother:

• He suffers from toxicosis, intolerance to smells and tastes.
• The uterus increases in size, causing frequent urination and pulling cramps in the lower abdomen.
• The body temperature of a pregnant woman rises to 37.3-37.5⁰C.
• There is a change in the amount of estrogen and progesterone in the blood.
• The amount of human chorionic gonadotropin increases.

6th week

At this time, registration at the antenatal clinic, clinical diagnostic testing of blood, urine, and bacterial tests take place. It is possible to conduct an ultrasound to confirm pregnancy and study the development of the baby.

Fetus:

1. The baby resembles a tadpole, with a large head and a long tail. Length – 4-6 mm. Constantly actively moving.
2. The heart muscle makes up to 120 beats per minute. (2 times more than an adult).
3. The neural tube closes.
4. The brain and cranium are actively developing.
5. The placenta reaches a weight of 800 g. The amount of amniotic fluid increases.
6. Facial features (chin, cheeks, lips, nose) are formed. The development of internal organs continues.

Feelings of a young mother:

• Toxicosis intensifies. Vomiting may occur at unspecified hours. Refusal to eat provokes weight loss.
• The woman is accompanied by a constant feeling of fatigue. The vessels of the brain become overstrained, causing migraines, dizziness, and loss of consciousness.
• Problems arise with the digestive system, constipation, diarrhea, and bloating.
• The growth of the reproductive organ is accompanied by cramps in the abdomen and lower back. Gradually decreasing pain, in the evening, and spotting may indicate a threat of spontaneous abortion.

7th week

Mid-first trimester of pregnancy.

Child development:

1. Fruit length is from 8-13 mm. The size of the head increases. The baby's brain is divided into 5 brain vesicles, the neural tube connects to the internal organs with the help of nerve fibers. The placenta thickens. Placental blood flow is completely improved.
2. The face takes on precise contours. The eyes are designated, and the formation of the optic nerves and retina begins.
3. The gastrointestinal tract consists of the stomach, pharynx, esophagus, rectum, and base of the bladder. The liver and pancreas are improved.
4. The respiratory organs are represented by the trachea, the rudiment of the bronchi.
5. The spinal column appears, the neck stretches, and the hands take on the appearance of shovels.

Woman's well-being:

• The week is characterized by increased hormonal changes, causing disruption in the process of biochemical reactions and exacerbation of chronic pathologies.
• Weight loss of 1-3 kg is possible, caused by refusal to eat due to toxicosis.
• Irritability increases, and taste preferences that are uncharacteristic of a normal state appear.
• The amount of creamy vaginal discharge increases. There is still a risk of miscarriage. It is necessary to monitor the shade of leucorrhoea and spasms.
• The skin becomes covered with acne, acne. There may be irritation, itching, and redness in the abdomen and chest caused by stretching of the skin tissue.

8th week

Pregnancy lasts about 2 months.

Baby changes:

1. The fruit takes on a human shape, 3-4 cm long. The back is straightened, the spine develops, and the tail disappears. Arms and legs appear, facial features are visible.
2. The heart and bronchi are fully formed, the trachea in the stomach produces gastric juice, and the intestines are enlarged.
3. The brain is growing. The foundation of lung tissue is laid.

For a pregnant woman:

• A small rounded tummy appears. The first weight gain is felt due to the growth of protective adipose tissue.
• The skin of the face is cleansed and the condition of the hair improves.
• I am worried about spasmodic pain in the lower abdomen and back. The discharge is white, the appearance of blood is dangerous and may indicate an incipient miscarriage.
• The uterus increases in size, and pressure is felt on the internal organs. Nausea is most common in the morning, and heartburn occurs in the evening.

9th week

Baby:

Future mom:

• Observes weight gain and increasing hunger. The daily food intake increases by ¼.
• Feels very tired and may have nightmares. There is heaviness in the legs, shortness of breath appears.
• Feels frequent vomiting and problems with teeth. The baby draws nutrients from the mother's body.

The uterine cavity grows rapidly, the walls of the organ thicken. Pressure on internal organs increases. Body temperature may rise to 37.5 degrees.

Week 10

New phase pregnancy. By this period, the baby’s body is fully formed and has limbs. The fetus reaches a height of 8-9 cm, actively floats in the amniotic fluid, has a complete face, with the makings of auricles. Eyelashes and eyebrows begin to form. Reflexes develop.

The child constantly sucks his finger, reacts to changes in the environment, distinguishes between daytime and nighttime. Heart rate reaches 100 beats/min.

The young mother's condition worsens due to:

• Spasms in the lower abdomen, lower back.
• Shortness of breath, heartburn. Thrombocytosis and stretch marks on the chest, legs, and abdomen may occur.
• Insomnia, nightmares. There is a conscious fear of losing a child.
• Increased growth of the uterus, occupying the entire pelvic cavity. Disappearance of the waist, abdominal growth, pain, engorgement of the mammary glands.

Week 11

The beginning of the 2nd trimester is “fruit formation”.

Child's condition:

1. Height is 9-10 cm. The baby moves actively and feels comfortable in the uterine cavity. The head occupies ½ of the body, the eyes are open, the hands are moving, the fists are clenched.
2. Reflexes are improved.
3. The respiratory system develops fully and the intestines begin to function.

Maternal body:

• Gains weight. The stomach is clearly visible, changes in the figure begin.
• The breasts increase by 2 sizes, the nipples become very sensitive.
• Stretch marks appear and veins enlarge.
• The uterus compresses the blood arteries, causing a lack of oxygen, dizziness, and headaches.
• Toxicosis disappears.

12-week

Time of the 2nd planned ultrasound diagnostics, 1st screening for the amount of hCG in the blood. The fruit is in constant motion. Clearly distinguishes the time of day, feels cold and warm. Sucking thumb, drinking amniotic fluid.

Fully formed:

• the brain (will actively develop in the future);
• the thyroid gland works in full, launching metabolic processes;
• external shape of the genital organs;
• gastrointestinal system.

Nails and body hair appear, and bone tissue accumulates to form the skeleton. The mental state of the young woman is normalized. Weight is gaining and the belly is growing a little. There is a frequent urge to urinate. The amount of vaginal discharge increases. There is a high risk of bacterial candidiasis.

Week 13

The final stage of the first trimester. The body and vital organs of the child are completing their formation.

The baby during this period:

1. It measures up to 14 cm in length, weight 70-80 g. Swims, sucks his thumb. Reacts to external stimuli emotional condition moms.
2. The skeleton and internal genital organs begin to appear.
3. The process of insulin production starts.

The young mother feels:

• Constant pain caused by a sharp enlargement of the uterus. There is a high probability of stretch marks developing.
• A burning sensation in the vagina is a symptom of a candidiasis infection.
• Shortness of breath, which occurs after physical exertion.
• Toothache caused by leaching of calcium from the body.

2nd trimester: 14 – 27 weeks of pregnancy

How the fetus develops over the weeks of pregnancy in the second trimester depends on the health status of the expectant mother. During this period, formation occurs bone tissue, feeding the baby using the resources of the mother’s body.

Week 14

The woman's body has adapted to motherhood. Starts the process of protecting emerging life. The expectant mother feels an improvement in overall well-being, a normalization of her mental state, and a decrease in irritability. An increased feeling of hunger forces you to increase your daily diet by ½ part. The uterus extends beyond the pelvis. Shortness of breath and heaviness in the legs appear.

The child is up to 11-11.5 cm in size. He tries to smile, turns his head, clenches his hands, and moves his legs. Facial features are almost completely formed, clear reflexes.

The following are fully operational:

• spleen;
• liver;
• pancreas.

The respiratory system starts. Heartbeat up to 110 beats/min.

Week 15

The beginning of the 5th month of pregnancy is accompanied by a 3rd blood test to determine the amount of hormones estriol, AFP, and hCG. Based on the research results, it is concluded that the fetus is prone to DNA pathologies.

During this week, a woman:

Child development:

1. The fruit is covered with transparent skin of a reddish hue, height up to 18 cm, weight 200 g. Constantly swims, moves its limbs, and responds well to external stimuli. In addition to the placenta, the baby is protected by a lubricant that resembles melted margarine.
2. Skeletal development continues.
3. The immune system enters the formation stage, interferon and immunoglobulin begin to be produced.
4. The gastrointestinal tract functions in full, the genital organs develop.

Week 16

The baby's height is up to 19 cm, motor activity is increased, the child can yawn, tumble, and stretch. Reacts well to external stimuli, distinguishes voices and loud music. Heart rate from 120-140 beats/min. The intestines are capable of defecation. The endocrine system is fully formed and ready to begin work.

A young mother feels the baby's movement. During the daytime, small bumps on the abdomen are observed, caused by blows from small legs and arms. The uterus puts a lot of pressure on the bladder, causing frequent urination.

When holding back the urge to go to the toilet, the likelihood of developing cystitis increases. Hemoglobin level is low.

Fainting, headaches, and dizziness caused by a lack of oxygen in the vessels are dangerous.

Week 17

19th obstetric week, half of the 9 month period.

Characterized by:

A woman's condition is determined by:

• Weight gain.
• Changes in body structure. The pelvis increases in size, the stomach is quite large.
• Constant feeling of hunger.
• Lack of oxygen in the blood. An increase in the level of leukocytes.

Week 18

The baby's size is from 25 to 27 cm. The baby moves. The respiratory system is formed, but does not work. Nutrients delivered through the umbilical cord. The ear bones begin to develop.

For a young mother, this period is accompanied by:

• Severe pain in the internal organs, caused by an enlarged uterus, displacement of the gastrointestinal tract. Heartburn appears.
• Increased hunger, thirst.
• Sleep comfortably in a side lying position.

Week 19

The expectant mother feels well. Weight increases by 4-7 kg from the original figures. The breasts swell and colostrum is released. The child reaches a height of 27 cm and a weight of 370 g. He gradually gains weight and improves his internal organs. Can detect taste and smell. The volume of bone and muscle tissue increases.

Week 20

A pregnant woman clearly feels the movement of the fetus. The enlarged uterus puts pressure on the respiratory system, causing shortness of breath and tachycardia. The navel begins to protrude.
The ratio of the sizes of the fetus and placenta changes in the direction of the child's growth. The cerebral cortex and nervous system are determined. The internal organs are formed.

21st week

The uterus compresses the diaphragm, making it difficult for the young mother to breathe. Gait changes due to a shift in the center of gravity. Leg cramps appear due to squeezing of the bloodstream.

The child's height is 30 cm, weight 500 g. The fetus moves, trying to find a comfortable position. The ears take on an anatomical shape. The baby reacts to the mother’s calm voice and recognizes it. Internal organs and systems are actively working. The formation of nervous tissue is completed.

Week 22

A young mother may begin to worry about late toxicosis. After eating, heartburn and pain in the abdominal area occur. The growth of the uterus slows down, the volume of the fetus increases. A strong sexual desire may occur.

The child is gaining weight (more than 500 g), moves actively, and is restless. Can sense all organs and parts of the body. The amount of hair on the head increases, eyebrows grow. Surfactant is produced, a substance that starts the respiratory system after birth.

22 week of pregnancy: what happens to the baby and mother:

Week 23

The woman's condition is satisfactory.

Characteristic features of the period:

• increased thrush;
• the appearance of false contractions;
• distinct movement of the baby;
• constant breaks caused by increased weight.

The baby is gaining subcutaneous fat. The skin becomes red and sags a little. The brain completes its formation and coordination of movements improves. The child is moving. Fetal height 34 cm, weight 1 kg.

Week 24

The pregnant woman's health is stable. Headaches, dizziness, and fatigue may bother you. The uterus is located 3-4 cm above the navel. The eyes become hypersensitive.

The child reaches a height of 34-35 cm and a weight of 1 kg. The accumulation of subcutaneous fat continues. Moves limbs, tugs on umbilical cord. He can no longer actively swim or tumble. The brain completes its development. The convolutions deepen, character traits and temperament are formed.

Week 25

A woman experiences increased heartburn, pain after eating, vaginal discharge, and uterine pressure. Hemoglobin levels decrease. False contractions appear at least once every 2-3 days

The child increases in size, cannot swim, tumble, and jerks his limbs. All organs and systems are formed. The gender of the baby is easily determined. This week, the testicles descend into the scrotum in boys, and the vagina appears in girls. Heart rate – 120 beats/min.

Week 26

The baby's organs are fully formed; in case of premature birth, the baby can survive if necessary care is provided. The brain improves and the immune system develops. Meconium is formed in the intestines - the first human stool. Fetal height 34 cm, weight 750 g.

The young mother's health is satisfactory. My weight is constantly increasing and I suffer from heartburn in the evenings. Headaches and dizziness became more frequent. The baby's movements can be clearly felt.

Week 27

The fruit reaches a size of 34-35 cm, weight 800 kg. Growth hormone will be produced. The baby's movements and gestures become more frequent. The immune system is being formed.
A woman's belly is getting bigger every week. Constantly accompanied by a feeling of fatigue. Swelling appears, possibly varicose veins.

3rd trimester: 28 – 36 weeks of pregnancy

How the fetus develops by week of pregnancy during the 3rd trimester is determined during a weekly visit to the gynecologist. By the beginning of this period, the baby is fully formed and is able to survive in the event of premature birth.

28 week

The weight of the fetus is 1.2-1.3 kg, and continues to gradually increase. The baby opens his eyes, turns his head toward the sound, and recognizes loved ones. Constantly hiccups. He can no longer swim freely; he now rests his head against the woman's ribs.

The young mother becomes clumsy, clumsy, and suffers from forgetfulness. The uterus grows (3-5 cm above the navel), strongly compresses the internal organs, causing pain and a feeling of heartburn. Swelling appears, especially in the hot season.

Week 29

For a woman, the time period begins with unpleasant sensations, concern:

• shortness of breath, lack of oxygen;
• swelling, heaviness in the legs;
• heartburn,
• chronic pathologies worsen;
• dizziness worsens in stuffy rooms.

The baby's movements can be clearly heard (up to 10 times per hour).

The child's skin smooths out and folds appear on the limbs. Begin to function:

• adrenal glands;
• body temperature regulator.

Hair growth grows, facial features become sharper. Height up to 40 cm, weight up to 1.5 g.

30th week

By this time, the woman should gain from 8 to 10 kg. The uterus is located 2-4 cm above the navel.
The child's movements can cause discomfort. The baby reached a height of 40-42 kg and weighs 1.7 kg. Tries to take the final position in which it will remain until the moment of birth. Constantly winces, expresses dissatisfaction and joy.

31st week

The child is fully formed, the skin is smoothed, and blood streaks disappear. Gallbladder produces bile, the liver purifies the blood. The lungs are closed, but spontaneous inhalation is attempted. The weight of the fetus is more than 2 kg, height is 40-42 cm.

The young mother feels strong tremors. She has difficulty climbing stairs. Tachycardia, varicose veins, constipation appear, and body temperature is poorly regulated. Shortness of breath, swelling, and heartburn increase. The baby's movement may be accompanied by pain in the internal organs.

Week 32

During this period, control ultrasound diagnostics with Doppler sonography is carried out.

Dangerous time passed for the child. A baby born at this stage is fully viable. His internal organs and systems are formed. Only the lungs, which begin their start at birth, do not work.

Week 33

The child and the expectant mother rapidly gain weight. The woman is worried about shortness of breath and heartburn. It is difficult to walk (the uterus and fetus are compressed by the veins and arteries). The headache gets worse and it is difficult to sleep. The baby is almost ready for birth, the immune system is strengthened.

Week 34

The fruit weighs 2.5 kg, length 40-42 cm. The nervous, respiratory, and immune systems are improved.
The uterus is located 5-7 cm above the navel. The woman experiences false contractions and itchy skin in the abdominal area.

Week 35

During this time period, the baby’s movements are intensely felt, and the stomach takes on a variety of shapes.
The fetus takes its final position, head down towards the birth canal. The baby's height is 47-48 cm, weight 2.5 kg.

36 – 37 weeks of pregnancy

How the fetus develops over the weeks of pregnancy and in the last days before birth is examined during medical examinations of the expectant mother. At this stage, the child is completely ready for birth and is viable without the use of medical manipulation.

36th week. The fetus accumulates subcutaneous fat. Sucking reflexes are constantly improving. Hormonal changes occur in the mother's body - oxytocin and prostaglandins are produced. The woman's total weight has increased by 11-13 kg since registration.

37th week.A pregnant woman is worried about the warning signs of labor:

• the fundus of the uterus descends;
• preparatory contractions intensify;
• body weight decreases.

The child has grown to 46-47 cm, weight from 2.7 kg. Ready to be born. Improves finger coordination. The fluff covering the fetal body disappears.

38-40 weeks of pregnancy

Fetal development at 38-40 weeks of pregnancy consists of a constant accumulation of subcutaneous fat at the time of birth. At this stage, the pregnancy is considered fully term and the baby is fully formed.

The expectant mother will most likely experience symptoms that herald the onset of labor:

After birth, doctors clean the baby, measure, assess its condition and hand it over to the mother for the first feeding.

41-42 weeks of pregnancy

How the fetus develops over the weeks of pregnancy in the event of a delay in pregnancy is determined by a specialist during urgent ultrasound diagnostics and Doppler sonography.

A delay in labor up to 41-42 weeks is possible in case of incorrect obstetric calculations. The fetus is fully formed, viable, ready for birth. If the gestation period is exceeded (up to 42 weeks), the woman is injected with labor stimulants. Further delay is fraught with hardening of the skull and the risk of birth injuries.

How the fetus develops by week of pregnancy: critical periods.

Fetal development is a complex philological process that lasts for 40 weeks.

Pregnancy is a normal state of a woman, during which internal organs, systems, the body and skeleton of a small person are formed from a cluster of cells.

Article format: Svetlana Ovsyanikova

Video on the topic: how the fetus develops by week of pregnancy

How the fetus develops by week of pregnancy:

Fetal development at 11 weeks of gestation:

Knowing how the fetus develops week by week during pregnancy, you can monitor the health of mother and baby. The doctor monitors whether the woman’s physical and psychological sensations coincide with the norms. This allows you to react in time and help mother and baby if necessary.

The expectant mother is calmer if she knows that the changes in her body are going according to plan. It is useful to know how the fetus develops by week of pregnancy. So mommy knows in advance what to expect, what to prepare for. Can tell the doctor if something doesn't go according to schedule.

How to correctly determine the onset of pregnancy

To track your pregnancy week by week, fetal development and sensations, you need to know what time to count from. How to determine the onset of pregnancy:

• if the mother knows when conception occurred, this is the most accurate option;
• The doctor determines the pregnancy period when he determines the size of the uterus, but in the first weeks it will not be possible to determine the period in this way, the uterus is still too small;
• by the date of the first day of the last menstruation, the date of conception is determined quite accurately, from this time the uterus begins to prepare for pregnancy;
• From 4-5 weeks you can conduct an ultrasound examination, it allows you to very accurately determine the period of the crumbs in the tummy.

Let's look at how the fetus develops over the weeks of pregnancy and a description of the changes in the small body. We'll tell you everything about pregnancy week by week.

Fetal development by week of pregnancy (photo)

1 Week

The obstetric week is not counted from the moment of conception, but from last day menses. At this time, the body is only preparing for a possible conception. If fertilization occurs during this period, slightly spotting spotting may be observed.

2 week

This time is considered the most favorable for conception. If a woman’s body is healthy and there are no pathological processes, then by the second week of the cycle the egg is mature and ready for fertilization. If conception has occurred, then at this time the fertilized egg attaches to the uterus, and from this moment the development of the fetus begins.

3 week

The embryo is still tiny, it is fixed in the uterus, and the formation of sexual characteristics is laid down at the cellular level. The placenta begins to form.

4 week

At this time, pregnancy can be determined by tests. The size of the embryo is no larger than a poppy seed, weighing about 0.5 g. The cells divide every minute, the crumb grows. During this period, the mother’s mood may change dramatically. Drowsiness is common. Increased sensitivity to odors appears. In the morning you may experience nausea and dizziness.

5 week

The baby at this stage looks a little like a tadpole: it has a small body and a large head. Its size is about 1.7-2 cm. The formation of the spinal cord and brain is underway. In the fifth week, the baby's blood type was formed. The thyroid gland, intestinal and urinary systems begin to form. The baby's tiny heart begins to beat.

week 6

The head and torso of the unborn baby are clearly visible. Tiny processes appear - legs and arms. Hormonal changes in the mother’s body lead to the fact that hunger may often be felt or, conversely, an aversion to food may appear. During this period, the expectant mother may lose weight due to the onset of toxicosis.

week 7

The placenta is fully formed: it performs protective and nutritional functions.

Baby development:

• the body is approximately the same size as the head, while there is still a small tail on the tailbone;
• the nervous system is being formed, both hemispheres of the brain are already formed;
• the heart works, it consists of 4 chambers;
• blood circulation is improved, the placenta nourishes the baby with oxygen, supplies nutrients, it protects him from germs, bacteria, infections and toxins;
• skeletal tissue turns into bone, the musculoskeletal system is formed, the baby can bend his elbows and knees;
• the hearing system is formed, the rudiments of teeth are laid, a nose, nostrils, and upper lip appear;
• the upper integumentary layer appears - the epidermis;
• a mound appears between the legs, which will later determine who is in the tummy: a girl or a boy.

8 week

By this time, almost all systems of the small organism have been established and their rapid development is underway. The tail is no longer visible. The baby can move his arms and legs and unclench his fingers. The eyes are now closer to each other, and the visual system is being formed. At this stage, the baby is already able to respond to touch.

Week 9

The arms and legs are well formed, the baby can move around in the amniotic fluid, he is still small and has not taken up all the space. The genitals are visible. The baby's eyelids have formed and he can blink involuntarily. The weight of the fetus is about 4 g, the height is about 3 cm.

10 week

The brain continues to develop. The head gradually rises from the chest. The fingers lengthen, although the membranes between them still remain. Sex hormones begin to be released, in boys - testosterone, in girls - estrogen.

11 week

The baby's weight is approximately 11 g, and his height is approximately 5-6 cm. The ears are formed and hair follicles are formed.

12 week

The fruit is about the same in length, about 12-14 g in weight. The intestines begin to contract and train gastrointestinal tract. The baby tries to raise his head and may start sucking his finger. He already reacts to sounds and is sensitive to pain.

Week 13

The vocal cords are formed, the torso begins to actively grow, and the growth of the head slows down. The sense of smell develops. Reactions to changes in temperature, light, noise, and music appear. The baby can already sleep for a few minutes a day. The brain can issue commands through reflex movements. Villi appear in the intestines. The skin is thin. Weight - about 20 g, height - up to 8 cm.

Week 14

The baby's weight is up to 50 g, height - up to 10 cm. Wakefulness and sleep modes appear. The respiratory system is being trained. Insulin begins to be produced. The baby’s heart reacts to mother’s stress, so you need to learn to calm down for the sake of yourself and your baby.

Pregnancy by week (fetal development with photos)

Week 15

Vision has been formed, now the baby will be able to see after it is born. He distinguishes between light and darkness. The sweat glands are working. Hairs begin to emerge. The process of ossification of the skeleton has begun, it will require a large amount of calcium from the mother.

Week 16

Now the fetus has taken on all the contours of a baby. The skin is still thin, it is covered with light fluff, and the blood vessels are clearly visible under it. Fetal weight - 110 g, height - 11-14 cm. Blood changes chemical composition, lymphocytes, erythrocytes, platelets appear. Hemoglobin synthesis is in progress. Eyebrows and eyelashes are visible on the face. The entire body of the fetus is covered with white lubricant; it protects the baby’s skin until birth.

Week 17

The baby is sleeping more and more. When he wakes up, he can stretch. The baby is very sensitive to sounds. He dislikes sharp and loud sounds. And his mother’s voice calms him down. Girls' internal reproductive organs begin to form this week. This week the strength of the baby’s kicks increases, they are frequent and noticeable.

Week 18

You can already feel the baby's first kicks. His musculoskeletal system is actively developing. Subcutaneous fat is gradually formed, muscles continue to develop, and the skeleton becomes increasingly stronger. The weight of the crumb is approximately 150 g, height is up to 14 cm.

Week 19

The baby sleeps up to 16-18 hours a day. The main sense organs are improved. The amount of subcutaneous fat increases. The respiratory system develops and strengthens. Weight reaches 200 g, height - up to 14-15 cm.

Week 20

With an ultrasound, you can see the gender of the baby, his face, and facial expressions. The baby is already yawning, tumbling, playing. The legs have become longer and more proportional, the head is now smaller compared to the body. The skin thickens: it now consists of four layers. Marigolds appear on the hands and feet. The head is covered with the first hairs.

21 weeks

When the baby moves, this can be seen on the surface of the tummy: tubercles appear on it. The baby’s weight is up to 330-350 g, height is up to 26 cm.

Week 22

The baby sleeps a lot, and even turns over actively in his sleep. The nervous system is improved, neurons are fully formed. Weight - approximately 410 g, height - up to 28-30 cm.

Week 23

The baby enters the REM sleep phase - now he can dream. The respiratory organs are not yet formed, but the baby begins to do the first test exercises. Weight reaches 400-420 g.

Week 24

Height - up to 25 cm, weight - up to 500 g. Oxygen enters through the umbilical cord, but the baby already knows how to inhale and exhale. The brain is formed, neural connections increase. The baby plays with the umbilical cord, makes faces, frowns and sucks his finger.

Week 25

The production of pigment begins in the child's hair. The baby can clench his hands into fists. He develops a grasping reflex. The weight of the crumb is 700 g, height is about 30-35 cm.

Week 26

The baby is gaining weight, now he is about 1 kg, his height is 33-35 cm. Subcutaneous fat accumulates, the skin becomes lighter. The baby becomes stronger, his kicks can cause discomfort to the mother.

Week 27

A child's brain grows and develops. The foundations of thinking are laid: memory and attention. Calcium is still needed in sufficient quantities, because the bones have not yet fully formed. Subcutaneous fat accumulates and skin color changes. The placenta forms the baby’s first immunity, which will protect him for the first six months.

Week 28

Subcutaneous fat accumulates, wrinkles are smoothed out, and the skin brightens. Convolutions are formed in the brain, intelligence is formed and grows, and emotions appear. This week, a Rh conflict between the fetus and mother is possible, so the doctor closely monitors this process and, if necessary, takes special measures. The baby's weight is about 1.3 kg, height is up to 37 cm.