Stage-by-stage development of the fetus in a woman’s body. Intrauterine development of a child: periods and stages with photos

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The birth of a new life is the most beautiful secret of nature. What could be more mysterious than the development of a child in the womb? The formation of a little person from a fertilized egg goes through a rather complicated path. Expectant mothers will be very interested to know how the child’s intrauterine development occurs week by week.

Initial development of pregnancy

Pregnancy lasts 40 weeks or 10 obstetric months. The term “obstetric month” implies 28 calendar days. But the beginning of pregnancy itself is considered the first day of the menstrual cycle. Thus, according to medical calculations, pregnancy lasts not 40, but 38 weeks.

So, fertilization occurred: the sperm penetrated the egg and formed a single cell with two nuclei. These nuclei, moving towards each other, form a zygote. A zygote is a one-celled embryo. This fact is the beginning of the development of a new life.

The zygote lives for 30 hours, after which its first division occurs. In subsequent days, cell division is repeated. On the fourth day of life, the embryo consists of 8-12 cells. By this time, this small lump reaches the uterine cavity, where the process of cell division intensively increases.

By the seventh day, the embryo already consists of hundreds of cells. On the eighth day, the embryo attaches to the wall of the uterus, where its walls have acquired a loose and thickened structure. The implantation process takes about 40 hours.

On the 14th day of the embryo's life, its back part thickens, preparing for the formation of the main organs.

Already in the second week after fertilization, pregnancy can be determined using tests. Already on the 3rd day of its life, a small embryo begins to produce a hormone - gonadoprin. All pregnancy tests are sensitive to this hormone.

At the end of the 4th week, a woman notices the absence of menstruation. The first symptoms of pregnancy will appear: nausea, dizziness, drowsiness.

During this period, the embryo is already called an embryo, the size of which is about 1 mm.

The development of a child in the womb can be divided into three main periods:

Blastogenesis - the first 15 days.
Organogenesis is the development of the embryo from 15 days to 10 weeks of pregnancy.
The fetal period is the development of the fetus in the womb.

If we divide the entire pregnancy into 3 equal periods, we get the following time periods: first, second and third trimesters. Each trimester lasts 3 months.

If a woman is not yet aware of her “interesting situation” and continues to lead an inappropriate lifestyle, then the embryo will most likely die at the blastogenesis stage. If the mother's destructive lifestyle does not change during the first 12 weeks, there is a high probability of miscarriage.

Embryonic development of a child in the womb

Embryo development is a key moment of pregnancy, since during this period all vital organs are formed, which will affect the baby’s health in the future.

Mommy should never be nervous: only peace and positive emotions!

By the end of week 5, the embryo consists of three cell layers: ectoderm, endoderm and mesoderm. Ectoderm is the basis of the nervous system, hair and skin. The endoderm will develop in the future into the gastrointestinal tract. The mesoderm will turn into skeletal and muscle tissue, and will also form the basis of the circulatory, excretory and reproductive systems.

At week 5, a kind of heart tube forms. We can assume that from this moment the embryo’s “heart” begins to beat.

A groove is formed on the back of the embryo, which is the basis of the spinal cord and the entire nervous system. It is very important for the expectant mother to take enough folic acid during this period. This substance promotes the full formation of the nervous system of the unborn child.

At week 6, the embryo takes on a C-shape. During this period, the formation of the primary intestine, skeletal cartilage, liver, kidneys, and thyroid gland occurs. The small embryo reaches 4 mm.

At the 7th week of pregnancy, women experience toxicosis. This period is characterized by intensive development of the brain. The mouth and eye sockets begin to form. The respiratory system actively develops, the heart begins to divide into chambers and arteries, and the spleen and gall bladder are formed.

At week 8, ultrasound can record the first movements of the embryo.

At week 9, the fingers on the upper and lower limbs, although they are still webbed. This period is characterized by the fact that the placenta begins to supply the embryo with nutrients and collect waste products. The embryo already has taste sensations.

At week 10, the membranes between the toes disappear and the tail disappears. The gender of the child is still difficult to determine at this age, but boys are already beginning to produce testosterone.

By the 11th week, the embryo weighs 5 g and measures 3 cm. This is the final stage of embryonic development; the embryo will subsequently be called a fetus.

Intrauterine development of a child by week in the second trimester of pregnancy

At 12 weeks, almost all organs of the fetus have formed and the child begins to actively move inside the uterus.

This is the beginning of the third period of fetal development. At this time, as a rule, an ultrasound is performed, which determines the quality of the child’s development and genetic abnormalities.

If intrauterine abnormalities are detected in the fetus, the woman is recommended to undergo additional tests. But final conclusions about chromosomal abnormalities can be made at 20 weeks with a control ultrasound. If serious pathologies are confirmed, doctors recommend terminating the pregnancy.

It is also worth noting that what older parents, the higher the risk of developing pathologies in a child. However, in this case, the opposite may be true: the percentage of talented children born is higher among older parents.

At week 13, the external genitalia differentiate. However, they can be distinguished already at 14-15 weeks using ultrasound. At this stage, the formation of the intestines occurs. The baby receives nutrition through the umbilical cord.

From the 14th week, the baby’s skeleton begins to form, which was previously represented by cartilage. The length of the arms corresponds to the proportions of the body, and the legs are formed with some delay. The baby can yawn and suck his thumb. He perceives the vibrations of sounds, distinguishes well the timbre of his mother’s voice and music.

That's why it's important for expectant mothers to listen to beautiful classical music, thus instilling good taste in the baby.

At week 15, the blood vessels of the fetus become visible, which are illuminated through thin skin. The skeleton and bone marrow continue to form.

At 16 weeks, a routine ultrasound is performed, where you can notice the movement of the baby’s eyes. The legs have become proportional to the length of the body and small marigolds begin to grow.

At 17-18 weeks, the small body is covered with primary fluff - lanugo. This is a natural lubricant that protects the skin from the aquatic environment. During this period, fingerprints are laid, which are genetically predetermined.

The baby weighs 200 g and is 14 cm tall.

At 19-20 weeks, fetal growth begins to slow down somewhat. At this stage, subcutaneous fat is deposited, which keeps the small body warm. The respiratory system is improving more and more, but it is not yet able to function independently.

Mid-pregnancy: intensive fetal development

Starting from the 20th week, the baby's teeth begin to form. The baby's hairs on his head grow more actively, but their pigment is formed a little later.

From the 22nd week, mothers begin to feel the baby pushing. His weight at this stage is 450 g, and his height is 19-20 cm.

From 23 weeks the baby begins to gain weight. The child begins to see, he even dreams. The brain is actively developing.

Muscular system and internal organs continue to actively improve. The respiratory system gains everything greater development. The first feces - meconium - accumulate in the baby's intestines.

The baby's skin is red and wrinkled. The child actively reacts to the position of the mother’s body and to external sounds. Taste buds have already formed on the tongue, thanks to which the child develops food preferences. It is important for mothers to understand this and try to avoid spicy and bitter foods, since the little one prefers sweets.

The beginning of the third and final trimester is week 27. By this time, all the organs of the fetus have already formed, and in the future they will be improved, as well as the development of the brain.

At week 29, the baby’s immune system is formed. The heart rate reaches 120-130 beats per minute. The baby may hiccup, as evidenced by slight tremors to the mother.

A child born at this stage can survive with certain care. His height is 37 cm and weight is 1150 g.

Prenatal development of the child in the last stages of pregnancy

For women who are preparing to become mothers of a healthy baby, it will, of course, be superfluous to talk about the right lifestyle. Alcohol, cigarettes, lack of routine, sleep and rest have a very detrimental effect on the health of the unborn child.

At 30-32 weeks, the baby’s subcutaneous fat layer becomes thicker. Some babies are already turning head down at this stage.

Convolutions appear on the surface of the small brain. The pupils can already detect bright light. When performing an ultrasound at this stage, you can notice how the baby closes its eyes from bright light. For this reason, it is important to avoid ultraviolet rays and avoid beach holidays.

From the 33rd week, the little man already becomes cramped in his mother’s tummy. At this stage, the fetus turns head down, preparing for birth.

If at this stage there are premature birth, then the baby has every chance to survive. However, he will be considered premature and will need special care in the hospital.

The baby's skin becomes pink and not so wrinkled, thanks to subcutaneous fat. It makes up 8% of the total body weight.

Thanks to the appearance of marigolds, the baby can scratch himself. Some newborns are born scratched.

From the 37th week there is an active improvement of the respiratory system. Babies born during this period can already scream. The vellus hair on the body thins, and on the head it grows rapidly. The child gains 30 grams of fat every day.

By this time, the stomach drops, and it becomes easier for mom to breathe. This usually happens two weeks before birth.

By this time the baby is ready to see the light. He is very cramped inside his mother: his knees are pressed tightly to his chin.

At week 39, the body becomes clean: the fluff remains only on the shoulders. The baby's intestinal system is filled with meconium and amniotic fluid.

At 40 weeks, prenatal development ends and a new person is born! Photos of newborns become almost the most important photo in the house. After all, what could be more exciting and beautiful than the birth of a small miracle!

– this is the most long-awaited period in the life of every woman. Not everyone knows how intrauterine development of the fetus occurs week by week, at what period of time which organs are formed, how the “transformation” from sperm into human occurs. Next, let's look at what the fetus looks like at each stage of development.

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Fetal development

ABOUT pay attention! The starting point is the date of the first day of the last menstruation.

During pregnancy, a woman should register with a doctor, to constantly monitor your health and intrauterine development of the fetus week by week.

In case of deviation, the condition can be corrected in a timely manner so that the child is born completely healthy.

The growth of the abdomen during pregnancy week by week can be observed as early as 4-5 months of pregnancy. But in very thin women it becomes noticeable already in the third month.

Pregnancy week by week, fetal development and the feelings of the expectant mother are described in detail below.

I trimester

The first stage of pregnancy is the most important period, since it is now that the new life, and the first stage of formation of internal organs and external parts of the body begins. Let's look at the detailed development of the embryo by day from conception to three months. Although it is correct to assume that the embryonic period lasts up to 8 weeks. Then the fetal period begins, when the embryo begins to be called a fetus. Let's consider all stages of pregnancy, starting from the first trimester:

How is a child born? In the first week, fertilization occurs, and the cell is called a morula, which by 6-7 days from conception connects with the mucous tissue of the uterus and attaches to it. From this moment development begins. If this does not happen, then the cell comes out during menstruation.
The morula turns into a fetus and an embryo is born, the placenta is formed and the umbilical cord grows. Also during this period, the neural tube is formed, which is necessary for the development of the central nervous system.
At this time, the formation of all future organs and systems occurs - digestive, respiratory, circulatory, etc. At the end of the third week, more precisely on the 21st day of development the heart begins to beat.
The liver, lungs, kidneys and spine are laid. At the same time, pits form on the head, which in the future will become the mouth, nose, and eyes.
The weight of the embryo is on average 0.4 grams, the height is about 2 mm. All systems are formed, limbs appear on the fingers nail plate. At the same time, the nasal passages and lips are formed.
From the 36th to the 42nd day, the placenta is formed, although there is still no connection between it and the embryo. The formation of the brain begins and the nerve endings begin to send signals that can be recorded on special equipment.
Blood circulation begins between the embryo and the placenta, that is, the umbilical cord is fully formed and a direct connection has been established between mother and child. The brain continues to develop, eyes and nose are formed and ears appear on the head.
Body length is approximately 1.5–2 cm. The inner and middle ears are developing. The face becomes human-like. The end of the week is considered the end of the embryonic period.
The blood vessels are strengthened and the osteochondral system develops. Joints on the limbs form, the child begins to move his fingers and clench his fists. The endocrine and cardiovascular systems are developing rapidly. Heart rate - 150 beats per minute, which allows for intensive blood pumping.
The body length is approximately 4 cm. The development of the nervous system already allows the future baby to respond to stimuli. He moves intensely, turns, somersaults and makes a lot of movements with his limbs. The woman does not feel these movements, since the size is still small.
The placenta fully performs metabolic functions and provides the baby with oxygen. The iris forms and the eyelids close completely. Ultrasound examination shows complete heart can be heard.
The genital organs – male or female – develop fully. The gastrointestinal tract is formed, the first intestinal contractions begin. By the end of the week, the baby is already swallowing the water in which it is located. There are already red blood cells and white blood cells in the blood.

Embryo at 8 weeks of pregnancy

Thus, we can conclude that the laying of the organs of the future organism begins at the stage of the first trimester, and by the second - all organs and systems are already present in the future baby, and now it will begin period of intensive growth.

II trimester

Let's look at the second trimester, fetal development by week of pregnancy.

At this stage, the second trimester of pregnancy ends. The fruit is almost fully formed. At the next stage, he will already be independent and viable. During this period, weight and height increase rapidly, and all organs and systems are finally formed.

III trimester

In the seventh month, the nasal cartilage thickens and the nail plate becomes slightly larger. It is believed that premature baby, born at this time, at proper care will live.

29 – 36. From this moment until the 36th week, the baby’s body weight increases rapidly and height increases. The development of the central nervous system ends. The upper layer of the epidermis is already more elastic, and the vessels are no longer visible through the skin.

Depending on the size of the fetus, it is already turned upside down and is positioned this way until birth. Dark green meconium accumulates in the intestines, which is expelled in the first days after birth. Cartilage and bones become more elastic. The skull does not completely fuse and a soft crown remains until birth. It takes up to a year for the head bone to completely heal.

Preparing for childbirth

At 36 weeks the pregnancy is considered full term. That is, childbirth at this stage is not considered a pathology. As a rule, a woman carries a baby for 40 weeks. But everything is individual. From this period the fetus is ready to go out. Intrauterine development has already ended, all organs are fully formed. The next stage of development will be after birth.

Important! In the last trimester of pregnancy, it is necessary to visit a gynecologist at least once every 14 days.

Video: fetal development by week

Conclusion

The mother can only wait for the birth, eat right and prepare for the birth of her baby. It is not recommended to eat a lot so that the fetus does not become very large, which can cause some difficulties during childbirth.

A woman is created by nature in such a way that at least once in her life she can give the world a new person. The period of waiting and birth of a child is the brightest and at the same time alarming time. But the expectant mother should not worry unnecessarily. She should know that a normal pregnancy is the key to the proper development of her child.

If a woman has a clear idea of how the baby’s body is formed throughout pregnancy, then it will be quite easy for her to do everything necessary to avoid the development of pathologies.

Should a woman know how her child is developing?

Knowing how intrauterine development of the fetus occurs week by week, future mom can correctly organize his diet and daily routine. Also, having complete information about what changes are considered normal, a woman will avoid a state of unreasonable anxiety.

Calculating the intrauterine development of the fetus by week, it should be noted that it lasts 40 of these calendar periods. In other words, a woman’s pregnancy lasts 280 days. During this time, the child undergoes a complete process of formation and development of all organs and systems.

Gynecologists examine the intrauterine development of the fetus by week and by period, of which there are two: embryonic and fetal.

The first lasts from the moment the egg is fertilized until the 8th week of pregnancy. During this period, after fertilization, an embryo is formed, which descends into the cavity and attaches to it. The fetal period lasts from the beginning of the 9th week until the moment of birth. The embryo transforms into a fetus, develops and grows.

It is also common to divide pregnancy into trimesters:

First trimester (1 - 12 weeks).
Second trimester (13 - 27 weeks).
Third trimester (28 - 40 weeks).

Now we can take a closer look at how intrauterine development of the fetus occurs week by week.

What happens during the embryonic period?

The most important thing from this period of development is the formation of the embryo. Over time, he begins to take on the shape of a person. The embryo is formed from the moment the egg is fertilized. This usually occurs in the fallopian tube.

From the moment the egg is fertilized, the development of the fetus begins.
According to the weeks of pregnancy, a morula is formed in the first seven days. It is a multicellular organism, a prototype of an embryo. The morula attaches to the wall of the uterus, and its outer cells form the umbilical cord and the outer membranes of the fetus. From the cells that are located inside it, the organs and tissues of the unborn child are formed.

How does the woman feel?

In the first week of pregnancy, a woman’s body temperature is slightly elevated, it is close to 37˚C. There are no hormonal changes in the body yet, but the expectant mother instinctively feels the changes taking place. From this moment on, a woman should be very careful about her diet and lifestyle, and exclude bad habits and follow your doctor's advice.

Every expectant mother will be very interested in how the fetus develops over the weeks of pregnancy. This information will help a woman prevent many dangerous conditions. The third week of pregnancy is alarming because it is during this period that there is the greatest risk of fetal rejection. The woman's immune system tries to reject the embryo. However, in response, a special protein is released that suppresses this protective reaction, and the unborn child has a greater chance of survival.

What happens to the embryo in the first weeks of pregnancy?

This period is also characterized by the formation of the placenta. The unborn child at three weeks is a ball with a diameter of 0.2 mm. But during this period, the lungs and respiratory organs, cardiovascular system, spinal cord and brain are actively formed, and the baby’s face and gender are also formed.
The woman begins to feel mood swings, drowsiness and fatigue, and early toxicosis may occur.

Further development of the fetus (this is already the fourth week of pregnancy) occurs very intensively. The unborn child develops three germ layers:

endoderm - the basis for the development of internal organs;
mesoderm is what the skeleton and bones will be formed from;
ectoderm - material for the formation of the nervous system.

The embryo already has a pulsating tube that develops into a heart. During this period, a heartbeat can be heard on an ultrasound. The respiratory organs and brain continue to form, and the face emerges more clearly. The embryo develops limbs, and by the end of the week they are already bending. The embryo is located in the placenta and maintains contact with the mother through this organ.

His heart is already beating!

During this period, many women are just learning about their pregnancy, especially if it is their first. Having found out this fact for herself, the expectant mother is interested in the main question: how does the fetus develop?

In terms of weeks of pregnancy, this is already the fifth calendar period. At this time, the embryo still bears little resemblance to a human being, but its heart already beats, its sex is clearly defined, and its kidneys, liver, pancreas and thyroid glands are formed.

Already at 8 weeks future baby takes on the outline of a person, his height is 3-4 cm. His arms and legs are already formed, his forehead is clearly visible, and the outlines of his eyes, lips and nose have been outlined. Internal organs are actively formed and developing. The stomach is already able to produce juice, the heart is formed, the intestines are growing, the trachea and bronchi have appeared. The spine, brain and limbs are actively developing.

By the end of the eighth week of pregnancy, the embryonic period of development ends, but the first trimester still continues. The unborn child has already acquired a human appearance, the placental-uterine blood circulation has been formed.

Fetal period

This stage begins from the 9th week of pregnancy and lasts until birth. The fetal period is divided into two parts:

early (9 - 28 weeks);
late (29 - 40 weeks).

During the early fetal stage, fetal development continues. In terms of weeks of pregnancy, this is the ninth. At this stage, fetal growth is 40-50 mm. He begins to show activity: bends his arms and legs, turns his head, brings his fingers to his mouth. But the mother is not yet able to feel this, the fetus is still too small.
Externally, the future baby looks like a little man with a big head. The eyes are still closed, and the skin is transparent. The genital organs begin to form, and this process will continue until the 20th week. The cerebellum and pituitary gland develop. The heart has four chambers. The tail disappears, being replaced by the tailbone.

The embryo turns into a fetus

At the tenth week of pregnancy, the embryo is already called a fetus and weighs 5 grams. His photographs already show isolated fingers, neck, elbows, knees, eyelids and upper lip.

There are taste buds on the tongue, the thickness of the umbilical cord increases.

The eleventh week of pregnancy is characterized by further development of the fetus. He already has eyelashes and baby teeth. The rectum is formed. The spinal cord is already producing red blood cells. The intestines are ready to go.

During this period, many mothers are referred by a gynecologist for a routine ultrasound. When undergoing this procedure, women are interested in the main question: is fetal development normal?

According to the weeks of pregnancy, the twelfth period begins. During this period, the child’s phalanges of fingers and earlobes are formed, he opens and closes his eyes. The intestines are already contracting, and the liver is able to secrete bile. The baby’s circulatory system is functioning, leukocytes appear.

At the twelfth week, the first trimester of pregnancy ends and the second begins.

The baby is actively growing

During this period, all fetal systems are formed, their development and growth are underway. At the thirteenth week, which marks the beginning of the second trimester, the baby reaches up to 80 mm in length and weighs about 20 g. At this time, the skeleton of the fetus is intensively formed, the pancreas begins to produce insulin.

The gynecologist will refer the expectant mother for the first genetic test. After studying the results of the ultrasound, the doctor will be able to tell you how the intrauterine development of the fetus occurs by week of pregnancy, and whether the indicators correspond to the norm.

At the 14th week, the baby’s face continues to form, facial expressions, eyebrows and hair appear on the head. On the body of the fetus, fluff and cheese-like lubricant are formed. The thyroid gland begins to work and its own hormonal levels develop.
The excretory system is functioning, the child is making breathing movements.

In the antenatal clinic, you probably saw a stand that depicted the intrauterine development of the fetus by week.

A table with this kind of information will be useful to every woman.

At the fifteenth week of pregnancy, the child develops hearing, the intestines form original feces, and the placenta thickens. The fruit weighs about 50 g, its height is 60 mm.

The expectant mother feels the baby's first movements

The sixteenth week of pregnancy is marked by an increase in the volume of amniotic fluid. The baby is actively moving, and the mother begins to feel it. The muscles on the face are developed and the baby at this stage is characterized by facial expressions. The bones and nails are almost completely formed, the skin is very thin and the blood vessels are clearly visible through it.

During this period, the gynecologist refers the woman to a second genetic screening. To do this, the expectant mother will have to undergo a second ultrasound. It clearly shows the intrauterine development of the fetus week by week. Photos that can be taken at this stage are presented below.

We count fetal movements

The third trimester begins from the 28th week of pregnancy, and the late fetal period begins from the 29th week. At this time, the baby is a little cramped in the womb, and his movements are not so active. Nevertheless, the woman must clearly monitor the tremors, their number should be at least 10 per hour. The brain is actively developing, and furrows appear on it. The teeth are covered with enamel, the eyes are capable of focusing. The baby's weight is about 1250 g and height is 37 cm.

At 30 - 31 weeks of pregnancy, the baby already takes its final position in the uterus. The fetus actively gains weight by increasing muscle mass and subcutaneous fat. If a child is born during this period, he has every chance of survival.

Further intrauterine development of the child (week by week this is already the 32nd calendar period) is characterized by the improvement of the immune and nervous systems. The child has his own waking and sleeping schedule, he has his own temperament. The baby weighs 1800 g and is 42 cm tall.

At the 33rd - 34th week of pregnancy, the baby actively trains the lungs and perceives the entire environment to the fullest. The skin of the fetus becomes smooth, the bones of the skull become stronger.

Baby getting ready for birth

At 36 - 37 weeks of pregnancy, the fetus prepares to be born. He’s already cramped in his mother’s belly and it’s becoming more and more difficult for him to move.

His body has enough fat reserves for thermoregulation after birth, his lungs are ready to breathe. There is no longer any fuzz on the body, but the hair on the head and nails are growing back.

At 38 - 40 weeks, all mothers expect childbirth. This can happen at any time. The child lowers and the mother begins to breathe easier. The woman carefully monitors the passage of the mucus plug and the appearance of contractions.

And finally, it happened! Mom and baby are now together. The baby is still very small, but full of strength to explore the new world. Now his status is a newborn.

Table of intrauterine development of the fetus by week of pregnancy

This article provides a complete description of how a child’s intrauterine development occurs week by week. The table below will serve as a kind of conclusion to all of the above and will serve as a reminder for the expectant mother.

Intrauterine development of the fetus by week of pregnancy

Gestational age in weeks	Fruit length, cm	Fruit weight, g	Development of organs and systems
4	0,1		Fertilization of the egg, its implantation, embryo and organ rudiments.
5	0,15 - 0,2		Layer of the liver, pancreas, upper respiratory organs, heart.
6	0,4 - 0,6		The appearance of the rudiments of the limbs, listening to the heartbeat, the neural tube closes, and parts of the larynx and middle ear are formed.
7	0,7 - 0,9		The trachea, esophagus, small intestine, adrenal glands and sternum develop. The brain is actively developing.
8	0,9 - 1,2		The embryo has a clearly distinguishable body and head, which are equal in size. The rudiments of the nose, eyes, mouth and reproductive organs are formed.
9	1,3 - 1,5	1	The cerebellum develops, fingers on the limbs form.
10 - 11	2,7 - 3,5	4	Joints, upper lip, ears, external genitalia, and the beginnings of baby teeth develop.
12	9	20 - 25	The face is formed, the intestines contract, the liver produces bile, the child moves.
13	10	28	The limbs are fully formed. The pancreas produces insulin.
14 - 15	12,5	50 - 90	The excretory system is active, the child produces urine.
16	16	120	Let's distinguish the sex of the fetus. The skin is very thin, muscles are forming. The child does not move so chaotically, the mother feels the first tremors.
20	25	280 - 300	There is fluff and cheese-like lubricant on the baby's skin. The intestines form original feces. The child is able to hear.
24	30	600 - 800	The work of the kidneys is activated, the fetus dynamically gains weight.
28	35	1200	The muscles and reproductive system of the child are formed.
32	40	1500 - 1600	The sensory organs and nervous system are actively developing: the baby is able to see light and feel taste.
36	45	2400 - 2500	The child quickly gains weight and his activity decreases.
40	50-52	3200 - 3500	The baby is ready to be born.

Of course, it is best to study this information when you are just planning a pregnancy. Then a woman has a better chance of properly organizing her diet, regimen, and intake. essential vitamins and minerals. However, information about the intrauterine development of the baby will always be timely and interesting for the expectant mother, regardless of the duration of her pregnancy.

At what stages of pregnancy, what organs and systems are formed in the baby? So, a new life was born, the greatest miracle of miracles happened! How do a few tiny cells turn into a person? This 9-month journey is full of secrets and wonderful discoveries! How long does it take for the baby’s main organs to form and how does the baby’s mother feel?

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Photo gallery: How long does it take for a child’s main organs to form?

First month (0-4 weeks)

On the seventh day after fertilization, the fertilized egg is fixed in the uterus. At the 3rd week, the embryonic period of development begins - all vital human organs and systems are formed. The baby's heart begins to contract on the 23rd day. The baby looks like a tiny (up to 7 mm) bean floating on the embryonic cord.

Mother

In the 2nd week of pregnancy, the level of hormones in the mother’s blood changes and pregnancy can be established by analyzing the hormone human chorionic gonadotropin. The first trimester is a crucial time for the formation of the organs of the unborn child, so you need to monitor your lifestyle. It is advisable to spend more time outdoors, avoid overload and stress. As a rule, in early pregnancy, the mother experiences drowsiness. The body knows what it is doing: now all resources are spent on building the baby’s systems, and you need to rest more. Some women experience toxicosis. Correct mode nutrition and sleep helps improve well-being. Many women complain of breast hypersensitivity and frequent urination.

Second month (5-8 weeks) baby

In the 5th week, the liver and other organs are formed, the heart and circulatory system are working. Facial features are outlined, you can see the nose, ears and eyes, teeth are formed. The baby already has a stomach and esophagus, a pancreas and an intestinal rudiment. The baby reacts to changes in the position of the mother’s body in space. trains the vestibular apparatus. He develops nerve cells and a sense of touch. It reaches a length of approximately 30 mm.

Mother

In our country, benefits are provided for those who are registered with early dates pregnancy - up to 12 weeks. This is done so that mothers undergo all the necessary examinations on time and everything possible can be done for the health of the unborn baby. So plan your first visit to antenatal clinic(or family planning center). Complaints of constipation are common. For prevention, review your diet and try to walk more. Remember that holding stool for more than 2 days is harmful to the fetus, so be sure to discuss this issue with your doctor. Emergency measure- laxative suppositories with glycerin. Hormonal changes can affect the condition of hair and skin.

Third month (9-12 weeks) baby

All systems continue to evolve. The formation of the baby's kidneys and blood occurs. The fingers have grown, and the rudiments of nails appear on them. The mouth already has a tongue, and taste buds form on it. The baby reacts to the taste. The fetus begins to move, although the mother cannot feel it yet: it is surrounded on all sides by amniotic fluid. It feeds and receives oxygen through the umbilical cord. The first bones are formed. The baby already knows how to clench his fingers into a fist!

Mother

The placenta develops. Although the baby is still very small, some women's bellies begin to enlarge. Try to wear loose clothing. Problems with stool may begin. Do not overindulge in foods that cause bloating (cabbage, brown bread), monitor bowel regularity and eat less, but more often. After 8 weeks of pregnancy, as a rule, the first ultrasound is performed. Follow your gynecologist's recommendations and try to get more rest.

Fourth month (13-16 weeks) baby

Congratulations, your child is now officially called not an “embryo”, but a “fetus.” At this time, the digestive system develops, the skeleton strengthens, and the fetal excretory system begins to function: the baby swallows a little amniotic fluid, which is then excreted. The endocrine system begins to function. Already in At 14 weeks, the fetus reacts to changes in the taste of the amniotic fluid. With the help of an ultrasound, you can sometimes see whether mom and dad are expecting a son or a daughter. The baby’s blood type and Rh factor can also be determined. The fetus’s brain continues to actively move. legs, some babies begin to suck their thumb.

Mother

The formation of the placenta ends, which becomes the main source of nutrition and oxygen for the baby. Previously, these necessary functions were performed with the help of the corpus luteum, which matured in one of the ovaries. In the second trimester, toxicosis rarely torments women. Pregnant women have adapted to the new level of hormones, psychologically come to terms with their new state and begin to enjoy it greatly. True, memory and concentration usually continue to deteriorate. Swelling of the extremities occurs. Monitor your blood pressure, do not forget to take tests on time in order to take timely measures and prevent anemia. Some mothers may feel the first movements of the fetus.

Fifth month (17-20 weeks) baby

The lungs are actively forming, the spleen (hematopoietic organ) begins to work. sebaceous glands. If you monitor your baby using an ultrasound. you can see him making faces. The baby begins to respond to sounds - turns its head in the direction of their source. By the end of the fifth month, the length of the fetus reaches 20-25 cm, the baby weighs about 300 g.

Mother

A gynecologist uses an obstetric stethoscope to listen to the fetal heartbeat. Usually women themselves begin to feel the movements of the fetus, which brings great joy, because this is the first contact with the baby! Under the influence of estrogens, the nipple circles darken and may appear dark spots on the face. The baby is growing, and the mother’s back feels increased stress.

Sixth month (21-24 weeks) baby

The baby gradually begins to make breathing movements. Hair appears on the head. The parts of the brain are differentiated. The operation of all systems is being improved. The muscular system develops: the baby actively moves, swims in amniotic fluid, and then rests - sleeps, just like an adult. He already has eyelashes and eyebrows. From the end of the 6th month, the baby already reacts to light and sound, as well as to touches on the mother’s belly. Sometimes the baby hiccups. By the end of the 6th month, the baby can already weigh up to 900 g.

Mother

Pregnant women usually complain of back pain and that it is increasingly difficult for them to find a comfortable sleeping position at night. In some cases, the legs begin to cramp. You may be lacking magnesium and vitamin B. Sign up for childbirth preparation courses - there you will receive advice on how to behave during childbirth and recommendations for caring for your child.

Seventh month (25-28 weeks) baby

The baby is actively moving and “communicating” with his mother. His lungs are developing. The baby’s endocrine system is already working almost autonomously, the stomach and intestines are functioning. Nervous system and the fetal brain are improving, usually at this time the eyes open slightly. Now the baby receives information through the senses: vision, hearing, taste and touch, and noticeably reacts to pain.

Mother

From this time on, uterine Braxton-Hicks contractions may appear: moments when the uterus painlessly tenses and immediately relaxes. This is not dangerous, just training before childbirth. But in such cases it is better to limit physical activity, lie down and rest. The uterus presses on the sciatic nerve, and women experience pain in the sacral area. Some women produce colostrum.

Eighth month (29-32 weeks) baby

Usually the baby turns head down in the uterus. With his current size, he can no longer “tumble” in the uterus as freely as he did before. If the baby is born now, he will be viable, but he will need a long “gestation” - special care.

Mother

For some women, the stomach drops somewhat and it becomes easier to breathe. A baby who rolls over can cause you discomfort if he kicks you in the ribs. There may be problems with urinary incontinence when coughing or sneezing: the uterus presses on the bladder, and the perineal muscles are excessively relaxed. Always carry your passport, exchange card, and medical insurance with you.

Ninth month (33-36 weeks) baby

The baby is almost ready to be born. After the 36th week he will be able to breathe on his own. But the development of important organs is still ongoing.

Mother

In the ninth month of pregnancy, most women experience anxiety and at the same time impatience. The spasms sometimes become painful - these are no longer Braxton Hicks contractions, but false contractions. Decide on the maternity hospital and birth tactics, talk to your doctor. Very soon you will see your baby, with whom you have already spent 40 long weeks.

Waiting for a baby to be born is a responsible and joyful time.

We will not be mistaken if we say that a successful pregnancy is a guarantee good health and proper development of the child.

In order to prevent the development of pathologies in a child, the expectant mother must clearly understand how the fetus develops and grows throughout the 280 days of pregnancy.

Knowing how it goes intrauterine development of a child, a woman will be able to properly organize her regime and diet and will not experience unnecessary anxiety.

Periods of intrauterine development of a child

During the intrauterine development of a child, there are 2 main periods:

Embryonic, which begins with fertilization of the egg and lasts 8 weeks;
Fetal, which begins from the 9th week of pregnancy and continues until birth.

Now let's take a closer look at how the human body is formed during these periods.

Each picture of the week is clickable to enlarge.

Period of embryonic development

The main task of this period is the formation of an embryo, which gradually acquires features characteristic of a person.

Starting from the moment the egg is fertilized in the fallopian tube, the formation of an embryo occurs.

At week 9, the length of the unborn baby is 40 - 50 mm. He becomes active, can bend and turn his head, and brings his hands to his mouth.

Externally, the fetus looks like a person with a disproportionately large head.

During this period, the skin is transparent and the eyes are closed.

Over the next two weeks, the act of sucking actively develops, he brings it to his mouth thumb, imitates sucking movements.

The formation of the lymphatic system and the formation of the thymus gland occurs.

The production of thyroid hormones begins. The adrenal glands and pituitary gland are actively functioning.

The fetus has an increasing influence on the mother’s body; the well-being of a pregnant woman largely depends on the intensity of development.

The late fetal period begins at 28 weeks and ends when the pregnant woman's amniotic fluid breaks.

It is reliably protected from external irritants, but if a pregnant woman experiences negative impacts, there is a high risk of premature birth of an immature child.

If infectious diseases occur, then the clinical picture of the fetal disease has all the characteristic signs.

There is an accumulation and preservation of all the necessary substances that the child will not receive through feeding after birth. Thus, calcium, cyanocobalamin, and iron accumulate.

Maternal immunoglobulins form passive immunity.

The late fetal period ends with the intranatal stage - delivery.

It is curious that from the moment of conception to birth, the baby’s growth increases more than 5000 times. And if you and I gained weight in the same way as a fetus does, our weight by the end of our lives would exceed the weight of our planet.