The formation of the fetus in the womb. The process of intrauterine development of a child

The development of a child in the womb occurs gradually during all 9 months of pregnancy. But in the first trimester (up to 12 weeks) the formation of all organs and systems of the body takes place - this is the most important stage in the development of the embryo, and in the second and third trimesters the child grows rapidly, gains weight, prepares for life outside the mother's womb. Consider the main points of development by week. By the way, it is these weeks (regarding the first trimester) that are considered the most dangerous for the baby. Any negative impact can lead to the formation of pathology or miscarriage.

What are the approximate stages of development of a child in the womb by week?

So, let's start with the 5th week of gestation (this is approximately 1 Week delay in menstruation in a woman, we consider in accordance with obstetric terms). The size of the embryo is only 3 millimeters, and the neural tube, heart and lungs, and thyroid gland are already beginning to form in it.

6 week- the embryo appears the rudiments of arms and legs. On ultrasound, the 2 hemispheres of the brain are already clearly distinguished. The formation of the intestine begins. The length of the embryo reaches 7 millimeters.

7 week. The interdigital spaces are already visible. On ultrasound, depressions (the eyes of the embryo), the nasal fold and auditory eminence are visible - the future ears. The length of the embryo is 8 mm.

8 week. During these 7 days, the embryo grows very quickly, at the beginning of the week it is 15-20 millimeters in size, at the end of the week it is 2 times larger. The embryo begins to form facial features. Ears, nose, neck appear.

9 week. The fingers and toes are already clearly defined. There is an intensive development of the circulatory system.

10 week characterized by the development of a sucking reflex in the fetus.

TO week 12 the fetus has good sensitivity, this indicates the development of its central nervous system. Reactions are noted not only to touch, but also to respiratory ones. The skeletal system gradually becomes stronger. This is how the baby develops in the womb during the first trimester of pregnancy.

IN 13-14 weeks the genitals of boys reach such sizes that they become visible during ultrasound examination on a good apparatus to an experienced specialist.

16 week characterized by ossification of the skull and increased mobility of the child, although most expectant mothers still do not notice the movements. The muscular system is actively developing. The baby already weighs about 180 grams and has a height of 13-14 centimeters.

IN 20 weeks During pregnancy, the baby becomes more and more like the cute babies we see on the covers of magazines. The head in relation to the body becomes more proportional. True, the body is completely covered with vellus hair, which, for the most part, will disappear by the time of childbirth, and there is almost no fat layer, which makes the baby look thin. But this does not prevent the child from actively moving inside the mother, and she already notices this. The height of the child reaches 19 centimeters, and the weight is 300 grams.

IN 24 weeks pregnancy, the child has the same height in numbers, weight 600-700 grams. He is actively moving, his heart is beating, and his beats are already heard through an obstetric stethoscope, if the dense fatty layer on the mother's abdominal wall and the placenta located on the anterior wall of the uterus do not interfere. Babies born prematurely at this time, doctors can go out with modern equipment, highly qualified neonatologists and other favorable conditions.

IN 28 weeks pregnancy, the child can already distinguish sounds, with ultrasound, if you conduct an experiment, it will be seen what kind of music or intonation of the voice the baby likes and which does not. Contrary to popular belief, the sound source does not have to be located in the mother's abdomen, since he hears sounds through his mother's ears. And from the side of the abdominal wall, it is reliably protected by amniotic fluid, which "extinguishes" almost all sounds. To understand how a baby hears while in the womb, try turning on some music and diving headlong into the bath.

IN 32 weeks the child is quite viable, is born with a weight of 1500-2000 kilograms. However, his respiratory system is not yet adapted to life outside the womb, and therefore he should be in an incubator, where a constant level of temperature and moisture is maintained. Many vital reflexes are missing.

IN 36 weeks the child is almost ready for birth, the fat layer on his body becomes larger. The skin becomes smoother, vellus hair falls out (at birth, they can remain in a very small amount on the back of the baby). The sucking reflex is present, which means that he will be able to suck on his mother's breast, which is very important both in terms of his health and the psychological contact between mother and child.

38-40 weeks- a healthy child is fully viable.

These are the main stages in the development of a child in the womb.

Interesting video on the topic.

2013-06-05T00:00:00

During this period, an organism arises from a fertilized egg, possessing primitive anlages of various systems and organs. Intrauterine development is divided into prefetal and fetal stages. The boundary between them is the end of the second month of the life of the embryo, when it turns into a fetus.

The beginning of time

Fetal development begins not from the embryonic period, but even earlier, because the embryo develops from a fertilized egg, and the fertilization of the egg is preceded by a long development of germ cells.

The pre-embryonic period includes the maturation of germ cells and fertilization.

If in the testes of men a constant renewal of germ cells occurs on average every 2 months, then in the ovaries of women there is no renewal. After the birth of a girl in her ovaries, there are only about 400 thousand cells - the precursors of eggs, which are given to her for life. In each menstrual cycle, one, less often two, eggs come out of the ovary. This process is called ovulation. After leaving the ovary, the egg enters the fallopian tube, where fertilization occurs - the fusion of female and male germ cells.

This fusion leads to the formation of a qualitatively new cell - a zygote. The zygote moves through the fallopian tube into the uterine cavity (this period lasts 7-8 days). When the zygote reaches the uterus, implantation begins - the introduction of the zygote into the wall of the uterus. The implantation process takes 3 days.

In the prefetal period, an intensive anatomical formation of the rudiments of organs that arose during the formation of the embryo occurs, and new bookmarks appear: the stomach and other sections of the digestive tract are isolated, the intestinal lining is divided into sections, the muscles are separated, and the skeleton is formed. In the second half of the prefetal period, the facial parts, the neck are formed, the circulatory system and sensory organs develop, the structure of the brain becomes more complicated, large digestive glands - the liver and pancreas - stand out. By the end of the second month, the rudiments of all organs are formed and occupy their permanent position.

During the fetal period, growth and functional maturation of the organs and tissues of the fetus occur, i.e. starting from this period, the organs of the fetus acquire the ability to function.

Second month. In the embryo (its length is 4 - 5 mm), the bookmarks of the limbs become noticeable. By the end of the second month, the length of the embryo increases from 5 mm (at the 5th pedal) to 25–30 mm. On the hands and feet there are fingers that are already able to move; but these movements are not yet felt by the mother. A rather long tail gradually turns into a small tubercle. The neck is being formed. The brain ceases to shine through the skin. The rudiments of the sense organs are formed from the protrusions and recesses of the brain, while the eyes are already almost fully formed. The size of the head is very large (it is about half the length of the entire embryo). A constant relationship is established between the main structures of the face, with the exception of the auricles, which are located very low. The body of the fetus begins to function: the brain sends impulses that coordinate the functions of other organs, the heart beats, the stomach secretes gastric juice, the liver produces blood cells. The rapid growth of the intestine, which began on the 6-7th week, leads to the fact that part of the intestinal loops ceases to fit in the small abdominal cavity of the embryo and goes beyond it. There is a so-called physiological umbilical hernia, which reaches full development by the end of the second month, and completely disappears by the 10th week. At the end of the second month (8 weeks), the body of the fetus is formed, there are rudiments of limbs, the rudiments of eyes, nose, mouth are visible on the head, the formation of genital organs begins.

Third month. The total length of the fetus, including the legs, is 7 cm, weight - 20 g. During the third month, the fetus grows rapidly and almost doubles its length. The head still remains relatively large, and by the end of the month it is about 1/3 of the parietal-coccygeal length. The facial part is very small compared to the brain part of the skull. There is a rapid growth of the eyelids, the edges of which fuse together at the 9-10th week of embryonic development. The eyes open only in the seventh month of pregnancy. The first rudiments of hair appear (on the eyebrows, upper and lower lips, on the forehead). The limbs make movements, the fingers and toes are visible, the first ossification points appear in the cartilaginous rudiment of the skeleton. Nail buds form on the fingers and toes. The fetus already knows how to grimace. Special studies have found that fetal facial expressions reflect changes in his mother's face while laughing or crying. The hands grow so large that the fetus can touch the head with its fingers, it can clench its fists. At the beginning of the third month, the urogenital and anus appear. By the structure of the external genital organs, it is already possible to determine the sex of the fetus. By the end of the third month, the skin begins to lose the transparency characteristic of it in the first two months of intrauterine life.

Fourth month. The total length of the fetus, including the legs, is 15-18 cm, weight - 120 g. The head begins to lag somewhat behind in growth. Fluffy hair appears on the body. The arms and legs are approximately the same length. The face is being formed, the skull is ossified, the formation of the muscular system is basically completed, the movements of the limbs become more active, but the mother is not yet perceived, the sex of the fetus is clearly distinguished. The fetus moves a lot, can suck its thumb. The skin has several layers. The functions of various body systems become more complicated. Using electron microscopy, it was found that the structure of nerve cells in the brain of a fetus of this age is almost the same as in newborns. It is already well possible to listen to the fetal heartbeat through the abdominal wall of a pregnant woman, the frequency of which reaches 120-150 beats per minute. By the end of the fourth month, an increase in the abdomen of a pregnant woman is already becoming noticeable.

Fifth month.(The total length of the fetus, including legs, is 22 cm, weight - 300 g). There is a faster growth of the body, and by the end of the fifth month of intrauterine development, the head is no more than l / 3 of the total body length. The skin is dark red. The subcutaneous fat layer begins to form. The skin is covered with fluffy hair. The sebaceous glands begin to secrete a fatty substance, which mixes with the scales of the epidermis and forms a cheese-like lubricant. This lubricant protects the fetus from constant exposure to amniotic fluid, and then facilitates its passage through the birth canal. Meconium is formed in the intestines. The lower limbs are noticeably lengthened. The fetus can be born alive, makes respiratory movements, but at this gestational age it is usually not viable.

In the amniotic sac, he is no longer so free, and his motor activity is increasing. In the 3rd week of the fifth month, a woman who is pregnant for the first time begins to feel these movements. Re-pregnant women notice them 10 days earlier. At first, the movements are very weak - women may confuse them with bowel contractions. Later, the movements of the fetus become more intense, and they can no longer be confused with anything. The first registration by the mother of fetal movements is an important sign that allows you to calculate the date of the upcoming birth.

Sixth month. The total length of the fetus, including the legs, is 30 cm, weight - 800 g. The skin of the fetus becomes wrinkled, apparently due to a discrepancy between the growth rate of the fetus itself and its skin. Eyebrows and eyelashes become noticeable. Skin patterns form on the fingertips. Each of them has their own drawing - unique and inimitable. During this period, the formation of cells of the cerebral cortex is basically completed. Their loss under the influence of any damaging factors is not replenished. A person lives all his life with the number of cells that has formed the cerebral cortex by this time. Fetal movements become more differentiated. By observing the fetus using ultrasound, German scientists have learned to determine by the position of the hands whether the fetus is awake or asleep. The organs and systems of the fetus continue to develop, learn new functions, but are not yet perfect enough and are not able to support the life of the fetus outside the womb.

seventh and eighth months. The total length of the fetus, including the legs, is 35-40 cm, weight - 1200-1700 g. The subcutaneous fat layer increases, and the skin becomes denser and smoother. In the seventh month of pregnancy, the eyelids of the fetus open. He knows how to open and close his eyes. By this time, his entire body is covered with delicate downy hairs. In recent weeks, weight gain is mainly due to subcutaneous fat, which ensures the maintenance of a stable body temperature after childbirth. All the most important systems of the body are sufficiently developed and can, although with great difficulty, with special care, support the vital activity of an infant outside the mother's body.

By about seven and a half months, the fetus can be born and survive. Babies born during the third trimester (from the seventh month until the end of pregnancy) are usually able to survive, although as the due date approaches, both the chance of survival and the ease of transition to an independent existence increase significantly. By the end of pregnancy, antibodies from the mother cross the placenta to the fetus, creating a short-term resistance to diseases to which you are immune. Premature babies receive less of this protection than term babies and are therefore more susceptible to infections.

Ninth month. The total length of the fetus, including the legs, is 45 cm. Due to the strong deposition of fat in the subcutaneous adipose tissue, the shape of his body becomes more rounded. Fingernails reach to fingertips. The hair on the head becomes thicker and longer. The fetus born at this time is viable, screams loudly, opens its eyes, a sucking reflex is expressed.

On the eighth - tenth months the growth rate of the fetus is reduced. It is already so large that it is cramped in the amniotic sac. In this situation, the most advantageous position, providing maximum mobility in the funnel-shaped uterus, is the position upside down. A normally developing fetus accepts it. Head presentation is most favorable for obstetric care. By the end of the ninth month, the fetal body is so perfect that it is finally ready for extrauterine life. Delicate hairs remain only on the forearms. Their severity and prevalence throughout the body may indirectly indicate insufficient maturity of the fetus.

Tenth month. The total length of the fetus, including the legs, is 50 cm, weight - 3000 g. By the end of the tenth month of pregnancy (38-40 weeks), the signs of prematurity disappear, the fetus is born mature. Relatively rarely, there is a discrepancy between full-term and fetal maturity. Under unfavorable conditions of development (mother's diseases, insufficient or malnutrition, etc.), a full-term baby may have signs of immaturity. Sometimes the opposite phenomenon is also observed: a child is born a little prematurely, but mature.

In the last month there is a faster growth of the lower limbs, and the difference in length compared to the upper limbs is smoothed out. However, it is only after birth that the legs become longer than the arms.

Recall that the correctness of the intrauterine development of the baby largely depends on his mother. During the examination, follow all the recommendations and the doctor's appointment - and the baby will be born healthy.

Fetal development by week Photo

Future mothers are anxious about the development of the baby, which they carry under their hearts and want to learn as much as possible about the processes taking place with them. during pregnancy , with interest study the stages of intrauterine growth of the fetus, carefully examine the pictures, which show in detail fetal development week by week.

Gynecologists start counting the gestational age from the first day of the last menstruation. The basic unit of time at pregnancy- a week.
The first weeks for the unborn child - are very important, at this moment the health of the body and its viability are formed.
Well if pregnancy will be planned , then the woman will begin to lead a correct lifestyle, save the baby from many health problems. Below you will find detailed information on the formation embryo in the womb, you will be able to consider the development of the fetus by weeks - Pictures with all stages of intrauterine growth and development, as well as a description of the ongoing processes at any stage of pregnancy.

Before turning to the photo with the stages of fetal development by week, let's briefly get acquainted with the main periods of the formation of the organs of a little man during pregnancy. At 5-6 weeks, an embryo 6 millimeters in size (like a pear bone) lives in a bubble with liquid. The formation of the nervous system takes place, the spine and brain appear. Two pairs of dimples for the eyes and ears are visible on the head. digestive tract originates already at this stage of fetal development.

Only 2 weeks pass and the main internal organs of the fetus are already formed. At the eighth week of fetal development, the face takes on the necessary forms, nostrils, the tip of a small nose, mouth, and tongue are visible. Starts to function inner ear . The fingers of the emerging baby are also looming.

12 weeks intrauterine development of the fetus- the age of a ten-centimeter embryo, in which the outlines of a human body are visible. Various systems and organs have already formed in the twelfth week of fetal development and are developing successfully. Modernized ultrasound equipment allows you to find out the sex of the baby and see the features of the face at this stage of pregnancy.

The beginning of the second trimester of pregnancy is the period of fetal development, when all the baby's milk teeth are formed. The gastrointestinal tract also develops at week 13, villi appear in the intestine that in the future will accelerate the process of digestion of products.

Up to 21 weeks of fetal development, the size of the baby allows him to move in the womb in any direction. The length of the fetus is 26 centimeters, weight - 0.4 kilograms.

A small organism is able to control its temperature from 29 weeks , the period of preparation for the birth of the baby and independent life begins.

At 31 weeks of development, the body is fully formed, it remains only to gain weight. The child is already able to feel, his condition may change depending on the mood of the mother. Hearing is developed enough to recognize voices. Sight and smell also function.

The baby is ready to be born at 37 weeks. Now childbirth can not be called premature. Of course, ideally you need to wait a bit. But the child can already absorb and digest mother's milk. , epithelium with villi appears on the mucous membrane of the stomach and intestines, through which nutrients enter the blood from food . Peristalsis is working, the first feces - meconium - have formed.

Now let's take a closer look fetal development by week of pregnancy, and also turn to the photo of the formation of the embryo in the womb with brief explanations. As you can see, already in the first weeks after conception, very important processes of formation of the structure of the fetus take place and the expectant mother needs to seriously change her lifestyle and adjust her diet from the first days. . Visit your gynecologist regularly and get all the necessary medical examinations.

Even pictures with the stages of intrauterine development of the fetus by week clearly demonstrate the importance of the ongoing processes of formation of the internal organs of the baby. We hope that the information posted by us will help you better understand the processes, happening in your body during pregnancy and we want to wish you baby was born healthy and beautiful !
NEXT ARTICLE:

In this article:

How does a child develop in the womb and is it necessary to take part in it at certain stages of this process? What are the periods of pregnancy and how long does it last? All this below.

The beginning of pregnancy - the birth of life

The average gestation period for a baby is 38-40 weeks, which is necessary for him to form in the womb. This time is enough for the child to be ready for the birth of a healthy and fully developed. In order to understand what is happening with the baby and at what stages, expectant mothers should track changes, adjusting their lifestyle and habits to the new situation.

So, pregnancy is usually divided into three main periods, which doctors call trimesters. Each such period is three months long. The most important one is first trimester. During this period, the formation of the internal systems of the baby's body begins. It is at this time that the expectant mother is especially acutely aware of the changes in her body, primarily associated with changes in the hormonal background. Almost all body systems are in the process of restructuring, including the genitals of the future woman in labor.

A new life inside the womb of a woman is born from one small cell, which after the prescribed 9 months will grow into a full-fledged human body, completely dependent on the mother until the moment of birth.

As a rule, the process of fertilization is carried out in the middle of the cycle. As a result of the combination of active
male sperm with an egg, one large cell is formed with a complete set of chromosomes - 46 pieces from the mother and father of the unborn child. It is from this moment that the process of fetal development inside the womb can be considered open.

The body of a woman is designed in such a way that after the fusion of the egg with the sperm, active cell division begins, even before it enters the uterus. Already at this stage, hundreds of cells are formed, each of which will be responsible for certain functions.

The path through the fallopian tube lasts about a week after the moment of conception. Then the egg enters the uterus and is securely fixed in it. The length of the embryo at this point is about 0.15 mm, that is, about the size of a large grain of sand or a pinhead.

First trimester: how it all happens

As soon as the cell is fixed on the uterine wall, the process of division begins to accelerate. Partially, the cells are converted into the yolk sac, chorion and fetal membranes. The rest is the beginning of the life of a new human organism.

Around the 5th week of pregnancy, you can see a serious progress in the development of the baby in the womb. He has a heart that starts beating.
In parallel with this, the nervous system and a number of organs responsible for hematopoiesis are formed.

A week later, the embryo is already beginning to form the brain, so far visually resembling an expansion of the neural tube. At the same stage, limb rudiments and visual vesicles with pigment discs are formed. By this time, the weight of the baby is up to 1.3 grams, and the length increases to 5 mm.

At the 8th week of pregnancy, expectant mothers are especially grateful to doctors for the opportunity to listen to how the baby's heart beats. High-quality ultrasound machines allow you to hear the rhythmic tapping of a small heart at this time.

And while the internal organs of the crumbs are almost invisible during an ultrasound examination, they are already there:
the digestive and cardiovascular system is laid, the process of formation of the bronchi begins.

In the first trimester, not only the embryo itself is actively developing, but also the placenta, which will take over the functions of life support for the fetus in the womb. It is she who will be responsible for maintaining a normal hormonal background, the process of gas exchange and the nutrition of the baby.

At the 11th week of development, the embryo can already be called a fetus, primarily because it begins to take on more and more resemblance to a person. His nervous system is already
knows how to conduct impulses, although so far they do not affect the internal organs.

During this period, a pregnant woman feels nausea, suffers from constipation, her heart rate increases and even heartburn appears. All these are symptoms of the first trimester of pregnancy, which by the second period in most women pass.

That is why expectant mothers are so looking forward to the onset of the second trimester - in order to feel better and finally calm down, remembering that the probability of pregnancy failure by this time is significantly reduced.

What happens in the second trimester?

Starting from the 12th week, the development of the child in the womb occurs at an accelerated pace. It is at this time that the baby's skeleton and abdominal organs are formed, the formation of the digestive system ends, about
as evidenced by the fullness of the intestine with meconium.

The baby's brain develops as actively as the skeleton and internal organs, grooves and convolutions appear on it. It is very important for the expectant mother during this period to spend more time in the fresh air so that the baby's brain receives enough oxygen.

Future women in labor especially tenderly and with trepidation remember the fifth month of pregnancy, during which they had the first physically tangible contact with the baby. Around the 18th week, the baby pleases future parents with movements, the nature of which the mother can determine by their frequency and strength.

The child reacts to the emotions of the mother, which he lets know by active movements in the womb. For a pregnant woman, tremors are the best proof that the baby is developing normally. If the movements have stopped and do not appear for a long time, it is urgent to be examined by a doctor.

In the second trimester, the formation of the baby's endocrine system begins, and by the middle of this period, the fetus is already working:

• adrenal glands;
• thyroid gland;
• pancreas;
• pituitary;
• sexual glands.

Around the end of the 24th week, the baby is already trying to imitate respiratory movements, although there is still liquid in his lungs and air does not enter them. Breathing rehearsal helps the baby to take the first breath after birth and reward the mother with a piercing cry, indicating the beginning of a new life.

In the second trimester of pregnancy, the expectant mother should try to be less nervous, walk more, relax and keep a sleep schedule, since the slightest stress can negatively affect the mental and physical development of the baby.

At the end of the second trimester, the baby's weight is already almost 700 grams, and its length reaches 35 cm. In the ultrasound pictures, you can see how the baby sucks his finger.

The final stage of the formation of a new life - the third trimester

At the last stage, the development of the child in the womb consists mainly in increasing the size of the baby. The belly of the expectant mother becomes noticeably larger: the formation of the fetus is coming to an end. The cerebral cortex is already almost formed by this time, and the baby
able to distinguish the sounds of the outside world. He listens to the voice of mom and dad, reacts to stroking the tummy, freezes or, conversely, begins to actively move at the sound of music.

In the womb, the baby during the entire period of formation hears the beating of her heart, which inspires him with a feeling of complete security. That is why, after the birth, the baby is first of all applied to the mother’s chest, so that he feels: his own heart is still there and the connection with his mother is as strong as it was.

During the last three months of pregnancy, most of the time the baby is preparing for the birth. The baby's eyes open, the blink reflex is honed, it actively gains mass by increasing the layer of fatty tissue, which then protects it from hypothermia during
outside world.

In the middle of the last trimester, the length of the baby is about 40 cm, and the weight is close to 2 kg. Inside the mother, it becomes cramped for him, so the intensity and duration of the movements by this moment are noticeably reduced. Around the 35th week, the development of the child in the womb moves to the stage of direct preparation for childbirth. The kid takes the correct position (head down) and patiently waits for the crucial moment.

In the last, ninth, month of pregnancy, the baby's weight is already approaching 3 kg, and every week he adds 200 g and by the time of birth he can weigh more than 4 kg. The vital systems and organs are fully formed, the baby's skin is smoothed, the lungs are preparing for the first breath. Expectant mothers at this stage of pregnancy need to be especially careful not to cause premature birth.

Is it necessary to develop a baby in the womb?

You now know how a child develops in the womb - it remains to talk about how to behave with an unborn child, whether it is necessary to communicate with him, teach him to music and what all this will give for his development.

Not all future mothers know that the baby in the womb begins not only to hear, but also to feel her mother, to experience her own emotions with her. That is why doctors insist that during pregnancy, expectant mothers pay special attention to communicating with the baby, trying to surround themselves with exclusively positive emotions.

It has been proven that a child in the womb listens to external sounds, among which the most important for him is his mother's voice. When the baby is especially active, only mom or dad can calm him down with simple strokes on the tummy and gentle phrases.

In order for you to be aware of the mental abilities of the baby, below are the data on his development by week.

The expectant mother during pregnancy, without even realizing it, begins to talk more with the baby, often she discovers new creative abilities, her musical preferences change. All this happens because it is important for the baby to use as many brain cells as possible in order to prevent their loss.

Starting from the 6th month of pregnancy, you can try to teach your baby some words that he will associate with sensations. For example, you can teach the child to understand the words "dark" or "light", turning the light on and off. By the end of the third trimester, the words known to the baby can be grouped into simple phrases, in addition, it's time to start introducing the crumbs to the world of music, including lullabies, classical music or children's songs.

Do not forget also that the baby in the last trimester of pregnancy has developed all the senses, so he can react to cold and hot, if you touch the abdomen with these objects, to voices, to bright light, to touch and even to the taste of amniotic fluid , which varies depending on what mom ate. Realizing all this, you can engage in the development of the baby in the womb in order to establish contact with him and further strengthen the emotional connection.

The onset of pregnancy is the beginning of an amazing time for the expectant mother. Seeing two cherished stripes on the test, I can’t wait to find out what lies ahead on the upcoming path of bearing crumbs. Today we will tell you how the fetus develops by weeks of pregnancy, what the mother feels at the same time, and at what stages all the organs and systems of the baby's body are formed.

Starting point: how to find out when the pregnancy began

The obstetrician calculates the start date for the expectation of a baby in a woman during the first visit to the antenatal clinic.

• The doctor performs a manual examination to determine the size of the uterus. This will help him understand what gestational age the uterus corresponds to.
• Also, the local doctor must specify the date of the first day of the last menstruation. This moment is taken into account, because. the uterine mucosa begins to prepare for pregnancy precisely from this period of time.
• You can find out the most reliable information about the gestational age with the help of an ultrasound examination. An ultrasound study can tell, to the day, when little life began. An examination even at the earliest stages (starting from 4-5 weeks) evaluates the size of the embryo, which allows the obstetrician-gynecologist to calculate the exact date of the onset of pregnancy.

In the first week after conception, the embryo is actively moving through the fallopian tube. After six days of active “journey”, it enters the uterine cavity. Under the action of progesterone (it is also called the hormone of pregnancy), the unborn baby is attached to the uterine mucosa, this process is called implantation.

If the attachment of the embryo has successfully taken place, then the next menstruation will not happen - the pregnancy has begun.

Intrauterine development of the child

The development of a baby inside the mother's womb, from the moment of conception to the moment of birth, is usually called a miracle, and there is every reason for this. Fortunately, medicine has studied quite well all the stages of the most important event in a woman's life - pregnancy. Every expectant mother can accurately imagine what will happen to her and her baby during all nine months.

There are three periods of intrauterine development of the baby:

1. blastogenesis- begins with fertilization and lasts 15 days;
2. embryonic period- starts from the 16th day and ends by the 13th week of pregnancy;
3. fetal period- from 13 weeks and lasts until the very birth.

Each period has its own chronology of events. The formation of the child's organs, vital systems in his body and his immediate growth naturally move in each period of intrauterine development. You can find out how this happens, what and when is formed in the summary table. It will be informative for expectant mothers who are interested and important information about the development of the child at all stages of pregnancy.

The development of pregnancy by week

The expectation of the birth of a baby in obstetrics is usually divided into three conditional parts:

• I trimester - from the beginning of pregnancy to the 13th week;
• II trimester - from the 14th to the 26th week;
• III trimester - from the 27th to the 40th week.

These trimesters contain 10 obstetric months. Conditional split table:

Before a detailed study of the process of fetal development in the mother's abdomen, it is necessary to familiarize yourself with the table of changes in the growth and weight of the future fetus:

Now let's move on to describing the development of the baby in the womb for each week of a woman's pregnancy:

1 Week

There is no talk of a fetus as such, since pregnancy has not actually occurred yet. The main sign that fertilization has occurred can be implantation bleeding. This phenomenon manifests itself as slightly spotting spotting approximately 6-7 days after conception.

2 weeks

This week from an obstetric point of view is considered as possible for conception. The egg in the female body matures by the 14th day of the cycle and is theoretically ready for fertilization. If, according to your calculations, the moment of conception has already taken place, then the second week is marked by the attachment of the fetal egg to the uterus. This moment is important, since from the moment of attachment the fetus begins its full development.

3 week

The embryo is similar in appearance to a microscopic berry; in the third week it is still only a set of cells. The size of the embryo is negligible, the maximum diameter by this time is 0.2 mm. But just during this period, the formation of sexual characteristics at the cellular level begins. Having gained a foothold in the uterus, the most important process of intrauterine development of the baby begins - the formation of the placenta. Before the formation and development of the basic systems of the body of the unborn child, there is very little left.

4 week

Obstetric 4th week - the period at which the expectant mother discovers two cherished strips on the test. The functional distribution of cells is in full swing in the embryo. Its size can be compared this week with poppy seeds. The weight is still quite insignificant and does not exceed 0.5 g, but the process of cell division occurs every minute and the unborn baby grows very quickly.

5 week

The embryo has already passed several stages of its development - the zygote, morula and blastocyst. Cells continue to divide rapidly, and by the end of the fifth week, the baby will already weigh at least 1 g, and the size will reach as much as 1.5 mm. On the fetal egg, you can already see the emerging sense organs - eyes, ears and mouth. The blood type of the unborn child was formed just in time for the 5th week of intrauterine life. The formation of the thyroid gland, as well as the intestinal and urinary systems, begins.

6 week

At this time, the largest parts of the body - the torso and head - are clearly distinguished in the unborn child. In the form of tiny processes, legs and arms are distinguishable with tiny fingers outlined on them. The weight at the sixth week of the embryo is up to 2 g, and the average size is about 4 mm. Cartilaginous structures are actively developing, the thymus gland is being formed. The main organs continue to develop: the heart, liver, lungs, stomach and pancreas. The baby develops muscle tissue, the external genitalia are outlined.

7 week

With the beginning of the seventh week, the embryonic period ends. The future baby is now called by another medical term - the fetus. At this time, the facial features of the crumbs are already slightly distinguishable. The rudiments of the nose, eyelids are formed, the ears and upper lip are visible. Outwardly, “unnecessary” organs are still present - gills and a tail, which will disappear a little later. The hemispheres of the brain are formed, cartilaginous tissues are continuously developing. The liver at week 7 is already capable of producing blood cells.

8 week

At week 8, the weight of the fetus is 1 g, and the length reaches 20 mm. If you look at an ultrasound examination, then the future baby will look proportionately like a grape. But every day the fetus looks more and more like a real man. The baby's face is already better marked, the nose has small nostrils, and the olfactory recipes are actively formed. His heart becomes four-chambered; in future girls, ovaries are formed, in boys - testicles; the arms and legs of the fetus at this time can already bend / unbend.

9 week

Many systems and organs are formed by the 9th week of pregnancy, but they do not yet fully function, but continue to develop. Palms are formed, the membranes between tiny fingers disappear. Lymph nodes are laid. The first reflex begins to develop - swallowing. The eyelids of the baby are formed and can involuntarily open and close. The fruit in size already resembles a large cherry berry - weight 4 g, height about 30 mm.

10 week

At week 10, the baby is actively moving and pushing. But these movements are so weightless that the expectant mother simply does not feel them. The muscles of the face, neck and pharynx begin to develop. The face is already formed, and in a few weeks the appearance of the unborn child can be seen on ultrasound. The rudiments of milk teeth develop. The cerebellum “acquires” neural connections that are subsequently responsible for reflexes. A small heart makes at least 150 beats per minute. Now the fruit weighs already 5 g, has grown by about +12 mm and resembles a strawberry.

11 week

The organs and systems of the crumbs have already formed by this time, some are working at full strength, while others continue to mature. The bronchi, lungs, trachea are actively developing; liver; intestinal tract; blood vessels; irises of the eyes. At 11 weeks on an ultrasound scan, you can see the outlines of the unborn baby.

12 week

The kid is already actively using some reflexes - imitating breathing and swallowing movements, involuntarily clenching and unclenching his palms into fists. The first contractions of the intestinal muscles (perylstatics) appear. The pancreas is formed and is already “learning” to produce bile. A unique pattern appears on the fingertips. The baby develops facial expressions, he can smile or wrinkle his face. Weight - up to 13 g, and height - up to 62 mm.

13 week

A week of active growth spurt for the unborn baby. The brain is already able to give the first commands to the reflex movements of the fetus. Sense of smell develops, vocal cords are formed. The body begins to grow faster, and the growth of the head, on the contrary, slows down. Digestive villi appear in the intestines of the crumbs. The baby's skin is still very thin, and riddled with blood vessels. The weight of the fetus increases to 20 g, and growth - up to 80 mm.

14 week

At week 14, all organs and systems of the unborn baby are being improved and continue to grow actively. The chest can rise and fall, as if breathing, this is how the lungs are trained. The process of hematopoiesis is formed, sweat glands, neck muscles become stronger every day. The weight of the baby at this time is about 27 g, and the height is 110 mm. The lifestyle, nutrition and well-being of the mother are very important - if these indicators are in order, then the baby feels good and does not experience any discomfort.

15 week

This week, the fetus has already formed vision and the necessary nerve endings to be able to see after birth. From the 15th week, ossification of the skeleton gradually occurs - a long-term process that requires a large amount of calcium. In toddlers, boys begin to produce the male hormone - testosterone. The kidneys excrete the first amniotic fluid. The muscles of the child are improved and strengthened. Fetal weight - 50 g, height - up to 104 mm.

16 week

At week 16, the future baby grows actively from the top of the head to the very heels. The weight is already about 80 g, and the height can reach 117 mm. The systems of the body function to the best of their ability, some of them are already “working” quite smoothly. Swallowing the amniotic fluid, it passes through the digestive tract and kidneys, and turns into urine. The skeleton becomes ossified, the child's legs lengthen. The baby is actively moving in the uterus.

17 week

The auditory formation of the unborn baby by the 17th week is smoothly completed. Weight approaches 100 g, and height becomes about 12 cm. The system of blood vessels develops and branches. The most important components of their own immunity appear in the baby's blood - interferon and immunoglobulin. In female children, the uterus is formed in utero. The strength of the child's tremors increases during this period, they become frequent and tangible.

18 week

The development of the fetus in this period of the second trimester is very intensive. The baby is growing so fast that it could already fit in the palm of your hand. The movements are palpable, the baby moves very actively at week 18. Often swallows amniotic fluid, which can lead to hiccups - this moment the expectant mother can notice by a slight twitching of the abdomen. Gradually, a layer of subcutaneous fat forms in the fetus, muscles develop, and the mineralization of the skeleton continues. Weight - about 150 g, height does not exceed 14 cm.

19 week

The child inside the uterus is actively growing, improving and gaining weight. By the way, by the 19th week the baby weighs about 200 g, and the height is about 14-15 cm. The body emphasizes the development of the brain, the improvement of the five basic senses. The amount of subcutaneous fat increases. The respiratory system continues to develop and strengthen. The period of wakefulness alternates with a period of activity, the baby can sleep up to 16-18 hours a day.

20 week

Outwardly, your baby has already become a real little man, and on an ultrasound scan you can already see the sex of the child, his facial features, watch facial expressions (which sometimes also show the character traits of the future child). The weight of the crumbs at the "equator" of pregnancy is approximately 250-270 g, and the average height is 16 cm. The child is active, turns his head, sucks his fingers, opens and closes his mouth.

21 weeks

At this time, you can already be sure that the child distinguishes sounds and hears what is happening outside the uterus. In terms of body proportions, the baby already almost resembles a newborn. The weight of the fetus is about 300 g, height is 19 cm. At this time, taste buds are actively formed, the composition of the blood is improved.

22 week

The twenty-second week is the period when the unborn child prefers to spend most of his time in a dream. But, nevertheless, in a dream, the baby actively turns over, the size of the uterus still allows you to change position. The baby is spinning, pushing, pulling the umbilical cord. Weight at this stage is about 350 g, and height is 20-21 cm.

23 week

The next week meets with the usual movements, although many babies prefer to “calm down” by 23-24 weeks and make their mothers worry about rare movements. The baby still has enough space in the uterus, so many of his pushes are simply not felt, so you should not worry. The weight is already moving towards the mark of 450 g, and the height is more than 22 cm, although it is worth remembering: all of the above parameters are individual.

24 week

Under the mother's heart, the unborn baby grows and gains weight - the indicator for many future children at this time is at least 550 g. This week, the development of the bronchi in the baby is completed, which is very important for the child's respiratory system as a whole.

25 week

From the 25th week, the child in the womb begins to produce pigment in the hair, giving them the color that is due to heredity. It is this color that the mother will see in the baby at his birth. Weight reaches 700 g, height - 23-25 ​​cm. Nerve connections and brain cells continue to form. In the fetus, training respiratory movements can be observed.

26 week

Tremors for a period of twenty-six weeks become strong, distinct, and many mothers may even complain about their intensity. The weight of the child is already at least 800-850 g, and the height is already more than 33 cm. The active strengthening of the bones of the skeleton continues, the rudiments of milk teeth in the gums are mineralized. Nails and hairs begin to grow.

27 week

The growth of the child at this time is about 34 cm, and the weight is approaching 1 kg. The baby becomes cramped in the uterus, and the legs can no longer be stretched out, so the baby takes the optimal position: it pulls small crossed legs and arms to the chest. From the twenty-seventh week, the baby is already gradually assuming the correct position in the uterus, but if he lies across or “sits on the priest”, then there is still time to roll over.

28 week

From the beginning of the 28th week of pregnancy, the weight of the fetus is up to 1300 grams, and the height is up to 37 cm. The development of muscle tissue continues intensively in the child. New convolutions are formed in the cerebral cortex. A Rh conflict between the mother and the fetus is possible, and at this time the obstetrician-gynecologist must take special measures.

29 week

The weight of the fetus is about 1500 kg, and the body length is at least 38 cm. It is time for the expectant mother to master the method of counting movements.

30 week

The full growth of the fetus reaches 36-38 cm, weight reaches 1.5 kg. The expectant mother may have several fears that are associated with future childbirth.

31 weeks

At the 31st week of pregnancy, the weight of the fetus will be about 1.6 kg, the full height is about 39 cm. The baby develops pain sensitivity. There may be disturbances in the night's sleep of a pregnant woman due to active and strong fetal tremors. It's time to explore the issues of anesthesia during childbirth.

32 week

The weight of the fetus is about 1.7 kg, the size from the crown to the heels is 40-42 cm. Sudden movements can cause dizziness and nausea in a pregnant woman. It's time to think about the possible presence of someone close to you at the birth.

33 week

The weight of the fetus by week 33 is approximately 2000 g, height is 42-43 cm. The mineralization of the bones of the fetus is almost complete. The expectant mother should from time to time count the movements of the fetus.

34 week

The growth of the fetus is on average 43-44 cm, weight 2.2 kg. The baby becomes very crowded in the uterus, and motor activity decreases. It is time for mom to discuss with the doctor the method of delivery: natural childbirth or caesarean section.

35 week

Fetal growth 45-46 cm, weight 2300-2500 grams. The fetus is almost completely ready for childbirth, but the lungs are not yet ready to perform the respiratory function. It's time to pack your things for the hospital. If the baby in the uterus has not yet taken the correct position, special exercises will help.

36 week

The weight of the fetus is approximately 2.5-2.7 kg. Full height is about 45-47 cm. At this time, the indicators of each crumb can differ greatly from the average, up or down. It's time for parents to make a list of things to plan and complete before the baby is born.

37 week

The thirty-seventh obstetric week of pregnancy is the time when the mother must be mentally prepared for the birth of the child. This is especially true of multiple pregnancy and the birth of children, starting with the second child. The weight of the child reaches 2.9 kg, and the height is within 50 cm.

38 week

The thirty-eighth week may be the last week of your pregnancy. The child gradually becomes heavier. The baby weighs about 3 kg, and the height is already 48-50 centimeters. Childbirth can begin at any time, so loved ones must be within reach at all times.

39 week

At the 39th week, the mother is not only physically, but already mentally prepared for childbirth. The baby weighs about 3 kg, and its height is about 48-50 cm. In size, the child at this time is similar to a miniature watermelon.

40 week

At the end of this week, the expected date of the birth of the baby may fall. The weight of the baby is already about 3.5 kg, height is about 51-55 cm. The baby is completely ready for birth. It remains to wait for the moment when he will make the newly-made parents happy with his birth.

Total.

This is how 40 weeks of pregnancy goes. A happy start to a new life - watch the video of how the baby develops in the mother's stomach:

Pregnancy development by months: how the mother's body changes and the baby grows

1st month

Mother. The chest becomes sensitive, touching it is painful. The uterus begins to grow gradually.

Child. So far, the future baby is called an embryo. For the first six days of pregnancy, he swims in the amniotic fluid, lives “autonomously” and is not yet connected with his mother. Outwardly, the embryo resembles a tiny auricle measuring 5 mm in size. By day 21, his heart begins to work; in parallel, at the same time, important organs are formed: the spinal cord and brain. By the end of the 1st month, the umbilical cord appears, connecting the baby with the future placenta.

2nd month

Mother. Pregnancy is outwardly not yet noticeable to either the expectant mother or others - the uterus is in the small pelvis, and its size is small. Changes continue to occur in the breast, it swells and increases in size.

Child. This month, changes are coming in the appearance of the unborn baby - facial features are emerging, the outlines of the eye sockets appear; there is the formation of tiny arms, legs and even fingers on them. The weight of the embryo at this time is up to 8 g, and the size is about 4 cm.

3rd month

Mother. An intensive growth takes place in the uterus, it develops, it already fills the small pelvis in size and almost reaches the womb. Very soon everyone will see that you are in position!

Child. By medical standards, your baby has already passed the embryonic stage and is now becoming a fetus. Its weight can reach 65 g, and its length varies from 10 to 12 cm. An important point in development is that in the 2nd month, the child has an inner and outer ear. The baby behaves very actively, moves its arms and legs, nods its head and clenches its fists. The growing child already has eyelids, and thanks to them he can open and close his eyes.

4th month

Mother. A rounded tummy is already looming, the waist begins to gradually “blur”. The mammary glands cause considerable discomfort due to their growth and sensitivity - you have to choose a suitable sleeping position for a long time.

Child. Your baby already has quite a tangible weight - up to 250 g. Most of the time the child spends swimming in the amniotic fluid, their renewal occurs every 3-4 hours. A fluff appears on the baby’s head, eyebrows and eyelashes appear on the face. In the intrauterine process of development, the first feelings and sensations begin to form in the child. The baby reacts to loud sounds and to a bright light source.

5th month

Mother. Almost every day, the belly of the expectant mother becomes larger and clearly protrudes forward. The uterus is located about 8 cm below the navel. Starting from 17 weeks, most expectant mothers begin to feel new sensations in the stomach - so far weak, but very pleasant jolts and movements of their baby.

Child. In the fifth month, the child's brain is actively growing, the nervous system is developing. The heart beats more often 2 times than that of the mother. The weight of the crumbs by this period can be up to 650 g, and the height is about 30 cm. By the 20th week, the baby is already able to suck his fingers on his hands, and at 24 weeks he can open his eyes and react to light.

6th month

Mother. The waist of a pregnant woman by this time becomes 8-10 cm larger. The size of the uterus increases so much that now it reaches the navel. The state of health and mood are good, the weight has not grown too much and nothing limits the activity of the expectant mother.

Child. It is time for the maturation of the respiratory system of the baby. The lungs begin to mature after 24-25 weeks of pregnancy. The child has already formed sensations of light and noise - when a sharp sound is heard, the baby may shudder. The first reflexes (hiccups, swallowing and sucking reflex) also appear and actively develop.

7th month

Mother. The size of the uterus by the seventh month of pregnancy reaches 24-28 cm in height, it continues to grow and increases with the child.

Child. The baby is already less active than at an earlier date. In most cases, the baby settles in the uterus head down, and sleeps for a long time. The weight of the child is already 1-1.2 kg, and the height is up to 37 cm. He is already learning to breathe, but the lungs are not yet mature enough - they will finally be ready for the breathing process at about 34 weeks, which is important for premature birth. By this time, the baby has already learned to recognize the mother's voice, and recognizes it when he hears it.

8th month

Mother. The body of the expectant mother continues to change - the uterus rises already by 30 cm, contracting from time to time, as if “rehearsing” the upcoming contractions. Colostrum appears in the breast. In the third trimester, the load on the female body increases many times over, and existing chronic diseases may worsen.

Child. The baby is growing and gaining strength. For bone mineralization, crumbs require a large number of calcium, which comes to him from his mother. The skin of the child becomes pink, smoother. From time to time, a mother can observe protrusions and “bumps” on her stomach at those moments when the baby is tossing and turning.

9th month

Mother. The body of a pregnant woman begins active preparation for childbirth. The uterus, together with the baby, weighs about 6-7 kg at this time, and its height is measured within 33 cm. In the third trimester, pain in the pubic joint, swelling and increased blood pressure are not uncommon.

Child. After the 38th week of pregnancy, the development of the intrauterine development of the baby can be considered complete. The baby is ready to be born. In the last month, the baby is gaining 10-15 g daily. Amniotic fluid is becoming less and less, the child is growing by leaps and bounds, and it becomes crowded in the uterus. In girls, the large labia cover the small ones; in boys, the testicles descend into the scrotum. The fluff on the body completely disappears, and little original lubrication remains. At the time of birth, the child weighs approximately 3-3.5 kg, and the height varies from 50 to 55 cm.

And finally, photos and recommendations from a young mother. Look at the photo of the growth of the abdomen during forty weeks of pregnancy. Have you photographed your belly week by week?