How does a baby's intrauterine development occur?

The first week of intrauterine development of the child

The fertilized egg, or rather the egg itself, moves through the fallopian tube into the uterus. The egg is an egg cell that has merged with a sperm. It contains all the information about the future child - gender, eye color, and possible talents! From the moment of conception, it is a person who has never existed before. (Unless, of course, you believe in reincarnation and transmigration of souls. By the way, even if you believe, the physical shell will still be different.) On the 3rd-4th day, the egg enters the uterus, and from the 5th to the 9th day after fertilization, the egg is implanted in the endometrium - the layer of the uterus that lines it from the inside. Here it begins to "grow" (take root) (if we draw an analogy with plants - it takes root) and receives nutrition from the future mother.

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The second week of intrauterine development of the child

Implantation is completed by the twelfth day. This is the real beginning of pregnancy. The egg begins to grow, which occurs through division. First, two cells are formed from one cell, then a transverse constriction appears, dividing these two cells into two more - there are four, then eight, sixteen, thirty-two, and so on. At the same time, two layers begin to form - outer and inner, by "screwing" one layer of cells into another. The diameter of the egg is approximately 1 mm.

The third week of intrauterine development of the child

This week is the most critical for the embryo. During this period, all unfavorable factors - alcohol, drugs, smoking, taking medications, infections, can cause irreparable harm to the embryo. In the third week, the future placenta, future blood vessels, sex cells are formed, the respiratory, digestive and nervous systems, skeleton, muscles, skin begin to form.

Fourth week. The embryo, which until now resembled a disk consisting of three layers, gradually turns into a cylinder. Individual organs begin to form. And the heart appears first. Its contractions can be recorded from the 23rd day of pregnancy. The oral and anal pits, the primary intestine, similar to a tube, the liver, pancreas, and spleen begin to appear. By the end of the first month, the embryo is about 5 mm long, and it resembles a bean with small growths that will later become arms and legs.

Fifth - sixth weeks

This period is very important because if the embryo is exposed to unfavorable factors, it may develop defects in the development of the central nervous system.

At this time, the embryo resembles the letter "E". The head is quite clearly visible, the tummy sticks out in the middle, rudimentary arms and legs are visible, and the tail is below. The arms grow faster than the legs. At this time, the nervous tissue is being laid down. Olfactory pits appear on the head - the future nostrils. The development of the bronchial tree begins.

The membrane separating the anal pit from the cavity of the primary intestine breaks through, and the intestine becomes open on both sides. The heart, the size of a small cone, consists of four chambers (two atria and two ventricles), separated from each other and the vessels extending from them by valves. The visual vesicles are formed - the future eyes. At this time, rudimentary ears can already be distinguished on the sides of the head. The total length of the embryo is about 2.5 cm.

Seventh - eighth weeks

The torso is formed and lengthened, reaching a length of about 3 cm. The shoulders begin to form, and later the limb is divided into the shoulder, forearm and hand. Muscles and nerves gradually form. The rudiments of the sex glands appear. The diaphragm separates the chest cavity from the abdominal cavity.

Changes occur on the face: two small slits appear - eyes, two grooves - ears. A small nose with nostrils is visible, and the mouth is bordered by lips (if the three lip processes do not come together, a "hare lip" is formed).

In the eighth week, the embryonic period ends - the embryo becomes a fetus.

In the eighth week, the fetus can already feel pain. Moreover, the receptors (sensory cells) of the fetus are more sensitive than those of newborns or adults.

At this period, fetal movements are already visible on ultrasound.

Usually during this period (in case of unwanted pregnancy) gynecologists perform an abortion. German operators together with doctors made a film about how the process of such murder occurs. The fetus waves its arms and legs away from the gynecologist's curette (the instrument used to perform an abortion), hides, in general, tries to save itself in every possible way, but...

Think before you have an abortion! Think about how to avoid unwanted pregnancy!

At the end of this period, the length of the fruit is about 3 cm, weight is about 3 g.

Ninth - tenth week

The fetus's face begins to acquire "human" features - the eyes on the sides of the head "converge" toward the center of the face. They are still closed, but there is already pigment on the iris.

During this period, the growth of the body accelerates, and the growth of the head slows down.

The liver and kidneys are almost developed, and the kidneys begin to form urine, which is released into the amniotic fluid.

The fetus loses its "tail". It can already suck its fingers, touch itself and the umbilical cord with its hands, push off from the walls of the uterus and swim in the amniotic fluid.

The rudiments of teeth begin to form, and the intestines are entirely located in the abdominal cavity.

The length is about 4 cm and the weight is 5 g.

Eleventh - twelfth week

All organs and systems begin to function: the liver secretes bile, villi form on the intestinal mucosa, which will absorb nutrients in the future, the intestines begin to peristaltize (contract), while continuing to rotate in the abdominal cavity so that it takes its usual position. The fetus begins to swallow amniotic fluid containing hairs, exfoliated skin cells, which, when digested, form the original feces - meconium.

During this period, fingernails and toenails begin to appear and the sex of the unborn child can already be determined.

The body length is about 6 cm and the weight is about 10 g.

Thirteenth - fourteenth week

By the 13th week, the fetus's taste buds are almost completely formed, and it begins to actively swallow amniotic fluid, preferring sweet amniotic fluid to waters of a different taste. Yes, at such an early age, it is already a gourmet! After all, it is not at all necessary for it to drink it, since it receives all the necessary nutrients from the mother through the placenta, which, by the way, is fully formed by the 13th week. Most likely, by swallowing amniotic fluid and sucking a finger, the fetus is preparing for extrauterine nutrition.

During this period, it begins to have phases of sleep and wakefulness. The face becomes cute, cheeks appear. The fetus becomes quite mobile, however, compared to earlier periods, its movements are smoother. Hairs and sweat glands appear on the body.

The length of the fruit is about 10 cm, and the weight is about 25 g.

The fifteenth to sixteenth week of intrauterine development of the child

Hair begins to grow on the head, the arms bend at the joints, the sense of touch develops. The fetus continues to grow, but new organs no longer appear, since they are already formed. It can frown, smile, blink its eyes in response to irritation.

The weight is already about 80 g, and the height is 110-115 mm.

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Seventeenth to eighteenth week

The skin is no longer so thin, but still transparent, red in color, the original hairs - lanugo - are clearly visible on it. Eyebrows begin to appear. Girls have a fully formed uterus and ovaries. The muscles become stronger, and the movements more active, and experienced (repeatedly giving birth) women can already feel them.

The height is about 13 cm and the weight is about 150 g.

Nineteenth - twentieth week

In boys, male genitalia are quite clearly visible. Ossification of the auditory ossicles is almost complete and the fetus begins to hear external sounds: the mother's heartbeat, her voice, the voices of other family members.

The brain volume increases rapidly. Starting from the 20th week, it increases by 90 g every month. The fetus begins to blink more often. The legs finally reach their final proportions, and it begins to push with them more and more strongly. The woman can already feel the movements of her baby in the belly. The fetus is about 15 cm long and weighs 260 g.

Twenty-first - twenty-second weeks

The skin becomes less red, but it is wrinkled and the blood vessels and internal organs are visible through it. More hair appears on the head. A characteristic imprint, unique to him, appears on the fingertips.

It is said that the taste of the amniotic fluid swallowed by the fetus can form the child's subsequent food preferences. In addition, since the fetus can already hear, it gets used to the voices of the mother, father and other family members. And if there is peace, love and respect in the family, then the newborn child will be calm; if there are constant scandals in the family, then the child will be nervous and restless. It has also been noted that if the mother reads a book out loud during pregnancy, then it can later become the child's favorite book.

From the 18th-19th week, start talking to your future child, create a positive emotional background! Thanks to this, you will develop harmonious, friendly relations with the child even before his birth and this will facilitate his adaptation to extrauterine life after birth.

The length of the fetus by the end of the 23rd week is about 20 cm, and the weight is 450 g.

Twenty-fourth - twenty-fifth week

The fetus sleeps less and is awake for quite a long time during the day. And since it does not sleep, its movements become more active: it makes 20 to 60 movements in 30 minutes. The fetus reacts to sounds coming from outside. It has quite complex facial expressions, often sucks its finger, sometimes hiccups. However, there is less and less room for movement.

If you want your baby to be musical, start playing music more often from the 24th week of pregnancy. But remember that fetuses prefer classical music, and rap, rock and other "rhythmics" make them nervous.

By the end of the 25th week, the fetus grows to about 22 cm and weighs 700 g.

Twenty-sixth - twenty-seventh week

The fetus begins to sense light, and if the light is too bright, it can even turn its head away. Naturally, it sees light when it opens its eyes. According to special studies, the electrical activity of its brain corresponds to that of a full-term newborn. But the most important action occurs in its lungs. A special substance, surfactant, begins to be produced there, which prevents the lungs from collapsing. Without this substance, the child will not be able to breathe air. And although by this time the fetus has passed only 2/3 of its development, it is almost ready for birth, and if this suddenly happens, it can survive. The prognosis for survival is especially favorable for girls.

The fetus is already about 25 cm tall and weighs about 1 kg.

Twenty-eighth - twenty-ninth weeks

The fetus makes breathing movements, but since it is in amniotic fluid, naturally only it gets into the lungs.

You may be afraid for your future child: "But he could drown!" No! He will not drown. Firstly, the amniotic fluid has the same composition of salts, glucose and other substances as the fetus's blood. Therefore, it cannot cause harm. Secondly, the blood vessels that carry blood to and from the lungs are still practically not functioning. They will only start working when the child is born. Thirdly, the fetus receives oxygen from the mother through the umbilical cord and placenta.

During this period, he opens his eyes completely (naturally, when he is not sleeping) and can already shift his gaze from object to object (although, apart from blood vessels, the umbilical cord and bright flashes from the outside, he has nothing to look at).

He already hears well and gets scared and even jumps at loud, sharp sounds, but calms down at the calm voice of his mother or father, or at smooth, quiet music.

Its dimensions are about 37 cm and its weight is about 1.4 kg.

Thirtieth - thirty-first week

The fetus is already so big that it becomes cramped in the womb and therefore it begins to move less, taking its characteristic collective pose: the head is tilted down and pressed with the chin to the chest, the arms are folded on the chest, the legs are bent at the knees, pulled to the tummy and crossed. In this pose it takes up the least amount of space.

Its eyes are grey-blue in colour, and its pupils react to light (they dilate in the dark and contract in the light).

The nails on the toes are already fully formed.

Its height is about 40 cm and its weight is about 1.7 kg.

Thirty-second - thirty-third weeks

During this period, the fetus usually takes the position in which it will be born - head down. But sometimes it does not have time to turn and takes the wrong position - breech or transverse, and then during labor there may be difficulties that can be resolved by surgery - cesarean section.

The skin begins to acquire a normal, pink color, it is no longer so wrinkled due to the fact that fat accumulates in the subcutaneous tissue.

During this period, the fetus has all the reflexes inherent in newborns. But they are much weaker, and the muscle tone is not as pronounced as in newborns.

The height is usually about 43 cm, and the weight is about 2 kg.

Thirty-fourth - thirty-fifth week

The placenta has already reached a large size - after all, the fetus needs increased nutrition.

The hair on the skin (lanugo) almost disappears, and the skin itself gradually becomes covered with germinal grease.

The head (if the baby is positioned correctly) begins to descend toward the entrance to the pelvis, and since there is less and less space for the fetus, it sometimes makes sharp and prolonged movements with its legs, trying to "straighten out". And then you clearly feel how it "tramps" on your liver.

Its height is about 45 cm and its weight is about 2.4 kg.

Thirty-sixth - thirty-seventh week

The baby's skin becomes completely smooth, it is still covered with vernix caseosa, but some of this vernix caseosa begins to separate and float in the amniotic fluid. Due to the sufficiently developed subcutaneous fat, the baby's body temperature is maintained at a higher level than the mother's body temperature. Quite a lot of meconium has already accumulated in the intestines, since the fetus actively swallowed amniotic fluid.

During this period, ossification continues, and the long tubular bones (femur, shoulder, shin) are almost the same as those of a newborn.

The height is about 48 cm, and the weight is about 2.8 kg.

During this period, if necessary, a cesarean section can already be performed. The extracted child is usually completely viable, and all organs and systems of its body can function as if it had been born on its own on time.

Why do you need to do a cesarean section at such a time? Firstly, if the mother has increasing symptoms of late gestosis (preeclampsia): increased blood pressure, swelling of the legs and lower abdomen, protein in the urine. Secondly, if a cesarean section has already been performed, and less than three years have passed since then. In this case, during labor, there may be a risk of uterine rupture along the old scar. Thirdly, if the mother suffers from diabetes, heart disease or other serious diseases, there is no point in waiting for natural labor to begin, which can worsen the condition of both the mother and the child. Fourthly, if the size of the pelvis does not allow the child to pass through the natural birth canal without hindrance.

In general, indications for a cesarean section are determined by the gynecologist, and, as a rule, not by himself, but by a medical council, which decides on one or another method of delivery.

Thirty-eighth - thirty-ninth week

The future child continues to grow and gain strength. It can hardly move anymore - it is so cramped in the womb. The skull bones have not yet grown together and form two fontanelles - large and small. Due to this feature, the baby's head will be configured during its passage through the mother's birth canal. That is, the skull bones can "crawl" over one another, reducing the size of the head, due to which it will be able to be born without any obstacles.

At the end of this period, the fetus already weighs about 3 kg, and its height is about 50 cm.

Fortieth week of intrauterine development of the child

The fetus is already fully prepared for birth and even wants it. It is only waiting for the moment when the mother's body accumulates a sufficient amount of hormones that ensure the onset of labor.

The baby's skeleton consists of 300 separate bones, since not all the bones have ossified and fused together (for example, the skull bones consist of six separate bones, while an adult's skull is a single whole). The number of bones in an adult is almost a hundred less.

50% of his body mass is fat. He is about 50 cm tall and weighs about 3.5 kg.