Embryonic development of the child by week. Pregnancy day by day, week by week. How the embryo develops

03.08.2019

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

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

Fetal development: stages and features

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

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

One cell produces trillions of new cells in 38 weeks. There are more than 200 species of them, and they are the biological building material necessary for the growth and development of a child in the womb, his birth and a full life on earth.

I trimester

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

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

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

Table 1

A week	Fetal development
1	Ovum development, ovulation, fertilization, blastocyst birth.
2	The movement of the blastocyst into the uterine cavity, where it will be fixed and continue its development.
3	The embryo takes on the shape of a human embryo. Nerve cells form the neural tube - the basis of the future spinal cord and brain of the embryo. A heart is formed, which up to this point resembled a clot of muscle cells. The size of the heart in an embryo does not exceed the size of a poppy seed. One cell suddenly contracts, setting all the cells in the heart in motion in a chain reaction. The heart of the embryo makes 20-25 beats per minute and is necessary for the embryo, since without it a full and correct distribution of oxygen and food is impossible. Blood cells are still primitive, but with each heartbeat they circulate through the thinnest (thinner hairs) blood vessels, delivering the necessary building material and oxygen to each cell of the embryo.
4	The period when a woman can feel pregnant due to changes in her hormonal system. The embryo is no larger than a bean, but every day it increases by 1 mm. Two black dots appear in the area of \u200b\u200bthe head - these are the future eyes. The heart of the embryo is still single-chambered and miniature, but already makes 80 beats per minute, accelerating the pace with each new day. “Kids” appear on the body of the embryo - in the future, arms and legs will form from them. From the neural tube of the embryo, areas of the spinal cord and brain are formed - the future central nervous system. The tissue growing from four sides forms the face. Its upper part grows down, forming an area for the formation of the nose and chin. The cheeks are shaped with tissue on both sides, forming the upper lip. Its connection is called the "philtrum", and it remains - it can be seen on the face of an adult. Improper fusion of this tissue contributes to a defect known as cleft lip. After the birth of a baby with such a defect, the help of a surgeon will be required. The human embryo is not much different from the embryo of any other animal. Only 1.5% of the genes indicate that this is a human embryo.
5	The first heartbeats of the embryo begin to be heard. Its size is only 3 mm, but it already has signs of the formation of the lungs, heart and thyroid gland.
6	The formation of the spine, upper/lower limbs and two hemispheres of the brain takes place, and the intestines are formed. The embryo is stretched, its length is 20 mm, and its body takes on the appearance of a human fetus. Eyes are formed from black dots, they are widely spaced and not yet equipped with eyelashes. Head size still dominates relative to body size. At the time of birth, the baby's head will be almost ¼ of his body, because the rest of the parts will not be able to keep up with the growth of the head.
7	The organs of vision develop, the organs of hearing are formed (the appearance of auditory elevations, eye sockets, nasal folds is observed on ultrasound). On ultrasound, it is already possible to clearly determine the presence of interdigital spaces, the formation of future fingers of the lower / upper extremities is taking place. The length of the embryo is 6 mm.
8	Active growth of the embryo is noted, the formation of facial features, the nose and ears are clearly distinguishable, the neck is visible. It can already be called a fetus, and outwardly it looks more and more like a person. This is an important stage in the life of the fetus. Previously, he received nutrients through the yolk sac - a floating ball connected to the umbilical cord. Unlike chicken yolk, the human yolk sac has no food reserves - in the first days of pregnancy, it produces the blood cells necessary to nourish the embryo. At this stage, he is unable to provide the fetus with the necessary amount of food, so the placenta becomes the source of nutrition for the fetus. It is connected to the umbilical cord and attached to the wall of the uterus. The placenta is a complex system that supports the intrauterine life of the fetus, consisting of an extensive network of the thinnest blood vessels. They are attached to the wall of the uterus and with their help the fetus draws all the useful substances it needs from the mother's body through the umbilical cord: water, oxygen, proteins, etc. Through the placenta, the fetus also removes its waste products.
9	At the beginning of the week, the length of the fetus is from 15 to 20 mm, weight - 3-4 g, and at the end of the week, these parameters almost double. The placenta controls the pregnancy process by producing the necessary hormones in the mother's body. The placenta performs the function of a filter, preventing harmful substances from reaching the fetus, but it is also unable to cope with some of their types. For example, alcohol, smoking products and many drugs easily cross the placenta to the fetus. In most cases, the mother's body tells her which foods her unborn child needs and which are dangerous for him. An active development of the nervous system of the embryo is observed, when the body of the previously immobilized fetus begins to twitch as a result of the occurrence of nerve impulses and reflex convulsions that are not yet controlled by the brain. The movement of the fetus is necessary to stimulate muscle growth and strengthen the ligaments. The brain is not yet able to control the work of the heart, which beats automatically. Its maximum speed is 157 beats per minute.
10	The brain begins to control all the vital systems of the fetal body, slowing down its heartbeat. It also now controls the movement of the upper/lower limbs. The development of the sucking reflex is noted.
11	In the period from 6 to 11 weeks, the embryo undergoes important metamorphoses, its body increases by almost 5 times. At the same time, more than 200 types of different cells are formed: nerve, muscle, liver, kidney, stomach and other cells that make up the human body. All parts of the body characteristic of a person are formed. Embryo growth - 7 cm. The development of the central nervous system of the fetus continues with the formation of its reaction to touch and breathing.
12	The size of the embryo is no larger than the mother's fist, but it is already more adapted to the environment in which it is located and less sensitive to various stimuli. The risk of his premature birth is reduced. The skeletal system is strengthened, further development of all systems and organs of the fetus occurs.

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

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

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

II trimester

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

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

table 2

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

The second trimester is a period in which there is an active development of all systems / organs of the fetus, the baby himself also grows and gains weight. He begins to actively move in his mother's stomach and declare himself. He has his own mode of wakefulness and sleep. He hears almost all the sounds that occur around him, distinguishes between darkness and light.

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

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

III trimester

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

As for the baby, he feels great. All his organs are already formed, he breathes on his own, hears perfectly, is able to distinguish tastes. The baby actively twists its legs, turns over, spins in the mother's womb in all directions. His head is already beginning to be covered with hairs, his body is covered with a lubricant that will facilitate his passage through the birth canal. The fetus is preparing for release, because soon it will be born. What changes occur with the baby in the third trimester of the mother's pregnancy can be seen in Table 3.

Table 3

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

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

Very often, during a woman's pregnancy, all the attention of loved ones is riveted to her. Everyone tries to help her in something, to fulfill her desire, to protect her from experiences and illnesses. The main thing is that loved ones understand that the health and life of the unborn baby depends on the health and well-being of the mother.

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

Pregnancy is a physiological process of development of a new organism. An embryo (fertilized egg) develops in the uterus, which then becomes a fetus. Pregnancy proceeds within 9 astronomical months (10 obstetric). Consider the development of the child by week.

fetus or embryo

In medicine, there are often two concepts regarding the period of bearing a child - this is "embryo" and "fetus".

Conventionally, intrauterine development of the fetus is divided into two stages:

1. The first embryonic period lasts eight weeks. The embryo that develops in the uterus at this time is called an embryo.

2. The fetal stage begins from the ninth week and during this period of pregnancy the fetus is in the womb.

First week

The first thing you need to clearly understand: what is the starting point. Speaking of the obstetric term: it is considered from the first day of the last menstruation. The embryonic gestational age is the true period from the time of conception. On average, it is less than obstetric by 2 weeks.

Pregnancy starts from the moment of fertilization. A mature male cell (sperm) fuses with a female cell. This process occurs, as a rule, in the ampulla of the fallopian tube. The egg and sperm carry half of the chromosomes of the future person. The result of their fusion is the appearance of a new zygote organism. This organism has a complete chromosome set that determines the sex of the child, eye color, and even character.

A few hours later, the egg divides exponentially and descends into the uterine cavity through the fallopian tube. This process takes place within 5 days.

As a result of division, a multicellular, blackberry-like organism appears. At this stage the embryo is called a morula. On the seventh day (approximately), the morula implants into the wall of the uterus. The blood vessels of the uterus are connected to the villi of the outer cells of the embryo, and subsequently the placenta is formed. Organs and tissues of the fetus develop from the internal cells of the morula. The outer cells give rise to the development of the umbilical cord and membrane.

As for the signs and symptoms of pregnancy at this time, they are not felt.

Second - fourth week

In the second week of pregnancy, external embryonic cells grow into the lining of the uterus, the formation of the placenta, neural tube and umbilical cord begins, subsequently from which the nervous system develops.

This is a difficult and important period. The baby begins to lay important systems and organs. In the third week, the rudiments of the digestive, circulatory, respiratory, excretory and nervous systems appear. In place of the future head, a wide plate is formed, which will subsequently give rise to the brain. The baby's heart starts beating on the 21st day.

This week the development of the rudiments of the liver, intestines, lungs and kidneys begins. The heart works more intensively, pumping more and more blood through the circulatory system.

At the beginning of the fourth week, the folds of the trunk and the rudiment of the spine appear in the fetus. On day 25, the neural tube is fully formed.

At the end of the week, the spine is formed, dividing the embryo into two halves with upper and lower limbs, and the muscular system.

In the fourth week, pits for the eyes are formed.

Fifth week

29-35 days of pregnancy is characterized by the onset formation of the following systems and organs:

circulatory system;
digestive system of the pancreas, liver;
respiratory system: trachea, lungs, larynx;
sense organs: inner ear and eyes;
reproductive system. The precursors of germ cells are formed;
nervous system. Parts of the brain begin to form;
limbs continue to form, the rudiments of legs appear;
nasal cavities and upper lip are formed on the face.

sixth week

In the sixth week embryo length reaches about 5 mm.

The placenta begins to form. But between it and the embryo, blood circulation has not yet been formed.
The parts of the brain continue to form. At this stage of pregnancy, when performing an encephalogram, it is possible to fix the signals of the fetal brain
The muscles of the face begin to form, and directly the eyes. They are already more pronounced. Eyelids are forming.
The heart completes the division into chambers (atrium and ventricles).
The development of the ureters begins, the primary kidneys appear.
The sections of the gastrointestinal tract begin to form.

Seventh week - end time the formation of the umbilical cord and the establishment of utero-placental circulation. Nutrition and respiration of the fetus is now carried out by blood circulation through the vessels of the umbilical cord and placenta.

At this stage of pregnancy, the embryo is still bent in an arcuate manner. The size of the head is almost half the size of the embryo; there is a small tail on the pelvic part of the body.

By the end of the week, the length from the crown to the sacrum grows to 15 mm.

Upper limb development continues, the fingers are already quite clearly visible, but they are not yet separated from each other. The fetus begins to make spontaneous movements of the arms, reacting to stimuli.

Eyes at seven weeks are already well formed and covered with eyelids that protect against drying out. Two paired elevations, future ears, are formed on the sides of the head. There is a blockage of the nose. Parts of the brain are developing intensively.

Eighth week

At the eighth week, the body of the embryo begins to straighten. Important systems and organs continue to form:

heart;
digestive system;
brain;
hearing organs
lungs;
reproductive system;
urinary system;

There is an intensive growth of the head and limbs: upper and lower. There is ossification of the skull of the long bones of the arms and legs. There is no longer a skin membrane between the fingers.

The face of a child is already more familiar to a person. Eyes covered with eyelids are well expressed on it, there are auricles and a nose, the formation of sponges is ending.

Starts in the eighth week of pregnancy fetal period of fetal development.

Ninth week

The size of the fetus at the beginning of the ninth week is approximately 22 mm. By the end of this period -31 mm.

Placental vessels improve, placental-uterine blood flow improves.

The joints of the fingers and toes are formed. The fetus is actively moving, shrinking fingers. The head of the child is lowered, closely pressing the chin to the chest.

During the ninth week of pregnancy changes in the cardiovascular system. The child's heart makes up to 150 beats per minute, pumping blood through the blood vessels. The composition of fetal blood is completely different from the blood of an adult. It contains only erythrocytes.

During this period, the organs of the endocrine system and the brain are actively developing, the structures of the cerebellum are being formed, the cartilage tissue is being improved, and the vocal cords are being formed.

By the end of the tenth week, the buttocks begin to develop in the child, the previously existing tail disappears. In the uterus, the fetus is in a bent state in a free position.

In response to stimuli, the fetus already performs not chaotic, but reflex movements. The baby makes movements, feeling contact with the walls of the uterus. He turns his head, bends and unbends his arms and legs, pushes himself to the side. Since the size of the fetus is still very small, the woman does not feel these movements.

The development of the diaphragm is completed, a sucking reflex is formed.

Eleventh week

The coccygeal-parietal size of the fetus by the end of this week increases to 5 cm. The body of the fetus is still disproportionate. The child has a large head, a small body, disproportionately long arms and short legs in all joints bent and pressed against the tummy.

The eyes continue to develop, the iris is formed, which determines the color of the eyes in the future.

The placenta during this period is already quite developed and well performs its functions:

removes waste products and carbon dioxide;
ensures the supply of oxygen and nutrients to the fetus.

The reproductive organs develop according to the male or female type. Improves the digestive system. The intestines are extended in length, fitting, like in an adult, into loops. Peristalsis begins, its periodic contraction. The child makes swallowing movements.

During the twelfth week, the baby's nervous system improves. And, despite the fact that the brain is still small, it exactly repeats the structure of the brain of an adult.

Reflex movements improved. The fetus at this stage of development can squeeze fingers into a fist, actively suck its thumb.

In the child's blood, leukocytes begin to be produced, single respiratory movements appear. The lungs of the fetus do not function before birth, but the baby imitates breathing, making rhythmic movements of the chest.

At the end of this week, the neck is clearly visible in the fetus, eyebrows and eyelashes appear.

thirteenth fourteenth week

At the thirteenth week of development, the size of the fetus is about 75 mm. Body proportions change. In relation to the body, the size of the head is no longer so large. Elongated limbs: both upper and lower.

Digestive and nervous systems continue to improve. Under the lower and upper jaws, the embryos of milk teeth appear.

The face of the baby is already fully formed, the auricles, eyes and nose are clearly visible.

By the end of the fourteenth week, the size of the fetus is already 8-9 cm. The proportions of the body are more familiar. The chin and cheeks appear on the face, the nose and forehead are well defined. The surface of the body of the fetus is covered with hairs that perform a protective function and retain the lubrication of the skin.

The bones of the fetus are strengthened, motor activity is enhanced. The child bends, rolls over, makes swimming movements.

The development of the ureters, bladder and kidneys ends. Improves the endocrine system. Pancreatic cells begin to produce pituitary cells and insulin.

Sexual organs change. In girls, the ovaries "go" into the pelvic cavity, in boys, the prostate gland begins to form.

fifteenth sixteenth week

In the fourth month of pregnancy, the weight of the fetus is 75 grams, the size is 10 cm. The blood vessels grow in length, their walls become stronger.

In connection with the ingestion of amniotic fluid, the original feces begin to be produced.

By the end of the sixteenth week, the fetus already has all the systems and organs. The kidneys work actively, urine is excreted hourly in the amniotic fluid in small quantities.

A child at this stage of development has very thin skin.. Blood vessels are visible through it, fatty tissue is practically absent. The skin of a child is bright red, covered with grease and downy hairs.

Eyelashes and eyebrows are well defined on the face. Nails are formed on the fingers, covering the edge of the nail phalanx.

The child begins to make grimaces, mimic muscles are formed. During this period, there is a semblance of a smile and a frown of eyebrows.

seventeenth week

Fruit size 14-15 cm, weight - about 150 gr.

Under the still rather thin skin, fatty subcutaneous tissue begins to develop. Milk teeth, continuing to develop, are covered with dentin. Germs of permanent teeth appear.

The child begins to respond to sound stimuli, actively moves when strong and sharp sounds appear.

The fetus changes its position. His head is raised, his arms are bent at the elbows, his fingers are all the time clenched into fists. The fetal heartbeat is felt more distinctly.

Eighteenth - nineteenth week

A wakefulness and sleep pattern is formed. The child sleeps most of the time.

A woman at this time may already feel the movement of the child as gentle jolts. The movements of the baby become more active when the woman is excited, which is reflected in the emotional state of the baby.

At the nineteenth week, the movements become more noticeable and frequent. They can already be felt not only by mother, but also by other people, putting their hands on their stomach.

Improving the endocrine system of the child. The pituitary, adrenals, thyroid and pancreas gonads function quite actively.

The composition of the blood has completely changed. In the blood, in addition to leukocytes and erythrocytes, there are lymphocytes and monocytes. The spleen begins to participate in hematopoiesis.

Twentieth week

The length of the body of the fetus increases to 25 cm, the weight reaches 340 grams.

There is an intensive development of subcutaneous adipose tissue. At the twelfth week, coordination of movement improves, a blink reflex appears. The fetus can squint, facial expressions are pronounced.

The activity of the child during the day varies. He reacts with violent stirring to a stuffy room and to loud sounds.

21st - 23rd weeks

Changes at this stage are characterized by:

At the twenty-third week, the body weight of the fetus is -500 g, the body length is about 30 cm. A pigment is synthesized in the skin, which affects the acquisition of a bright red color by the skin. Subcutaneous fat is still thin. The little one looks wrinkled and thin. The entire skin is covered with lubrication, which is more abundant in the folds of the body: axillary, elbow, inguinal.

The sexual organs continue to develop: in girls, the ovaries, in boys, the scrotum.

The child's breathing rate increases to 50-60 times per minute.

At this stage of development swallowing reflex appears. The baby constantly swallows amniotic fluid, which contains particles of skin lubricant. Swallowing water causes hiccups in a child, which a woman can feel in the form of rhythmic movements.

twenty fourth week

The movements of the child become more and more clear. The length of his body is 30-32 cm, the weight increases to 600 grams by the end of the week. The fetus occupies almost the entire space in the uterus, but can roll over and change position. Muscles grow strongly.

At the end of the sixth month, the child's sense organs are well developed. Vision is already functioning and when bright light hits the woman’s stomach, the baby closes his eyelids.

The fetus, thanks to well-developed hearing, already distinguishes sounds and reacts accordingly.

There is an emotional connection between the child and the mother. If the mother experiences negative emotions (longing, fear, anxiety), the baby experiences the same feelings.

twenty-fifth to twenty-sixth week

At the twenty-fifth week, the skin becomes elastic, the number of folds and their severity decreases due to fatty subcutaneous tissue.

passes intensive development of the bone marrow, which takes on the main role in hematopoiesis. The bones continue to get stronger.

At this time, alveoli are formed - elements of the lung tissue that, before the birth of a child, resemble deflated balloons without air. They will deal with the first cry of the baby.

The muscle tissue continues to grow. The length of the fetus is 35 cm, weight -760g. The child develops a sense of smell.

Sexual organs continue to form.

twenty-seventh - twenty-eighth week

The baby in the womb is quite active. His thyroid and pancreas, pituitary glands function well. An individual metabolism is formed.

The fetus by this age becomes viable. Fatty subcutaneous tissue accumulates. The skin is still bright red in color, vellus hair gradually begins to fall out, remaining on the shoulders and back.

Eyebrows, eyelashes and hair on the head become darker. The child opens his eyes more often. The cartilage of the ears and nose is still soft.

During this period, more active one of the two hemispheres of the brain functions, which affects who the child will be in the future: left-handed or right-handed.

Twenty-ninth - thirty-second week

The fruit has already grown enough. It occupies almost the entire space in the uterus, located in a certain position: down the head or buttocks. The movements are felt as periodic jolts of the arms and legs.

The load on the cardiovascular system increases. The lungs are prepared for the birth of a child, surfactant is produced. In the brain, the area of the cortex and the number of convolutions increase.

At the baby changing wake and sleep patterns. However, he still sleeps most of the time, actively moving during wakefulness, which is well felt by his mother.

The baby's eyes are already fully formed. They are closed during sleep and open during wakefulness. The fetus reacts to light by dilating and constricting the pupils. The color of the iris is blue (the same for all children). After birth, it changes.

The size of the brain increases. At this stage, it is 25% of the brain volume of adults.

At the end of the thirty-second week, the growth of the fetus is 43-44 cm, weight is about 2000 grams. The child in the uterine cavity is getting tighter. He moves less and less. The position of the fetus is fixed. At this time, there is little chance that the child will roll over.

The skin becomes smoother and brighter, an increase in adipose tissue. The layer of protective lubricant increases, vellus hair is more and more wiped.

The mass of the heart increases, the formation of the alveoli is almost completed, the tone of the blood vessels increases, the brain is already fully formed.

Thirty-fourth - thirty-eighth week

At the thirty-fourth week, the baby's skull bones are soft and mobile, due to the presence of fontanelles, which will close some time after birth.

Hair actively grows on the head, taking on a certain color, which will also change after childbirth.

The bones are intensively strengthened and the fetus begins to take calcium from the mother's body. A pregnant woman may experience convulsions at this time.

Every day the child adds 25-35 grams. In this period, the weight can vary greatly. All the internal organs of the child continue to improve.

The child becomes more well-fed. The fat layer is already well developed, the skin color is lighter. The lungs are fully formed. The cartilages of the nose and auricles are more elastic and dense.

The maturation of the digestive system is over. Contractions occur in the intestines and stomach to push food through.

The height and weight of the child varies greatly. The fetus is already completely ready for birth.

Thirty-ninth - fortieth week

14 days before delivery, the baby begins to descend and cling to the pelvic bones. The placenta gradually grows old, metabolic processes worsen.

in the fortieth week the uterus begins to shrink. A pregnant woman has sensations of aching pain in the lower abdomen. The head of the fetus takes root more closely to the pelvic cavity, the neck opens slightly.

Due to the softness and suppleness of the bones of the skull, the baby's head changes shape and easily passes through the birth canal.

Demchenko Alina Gennadievna

Reading time: 8 minutes

It is very interesting for all women who are preparing to become mothers soon to look into this period and find out what is happening inside them. In our technological age, you can see the development of an embryo on the monitor of an ultrasound machine and even take a photo. But you want details about how the embryo develops by day.

The development of an unborn child takes two stages:

Embryonic. It begins during the passage of the sperm into the egg and lasts until the ninth week of intrauterine development.
Fetal. Until the delivery of a woman.

Pregnancy lasts for ten months. The obstetric month takes, unlike the calendar month, twenty-eight days.

Embryo growth on certain days

After a couple of hours from entering the egg, the sperm begins the process of crushing. One cell is divided into two, four, eight and so on. During the first four days of the embryonic stage, fifty-eight cells, called blastomeres, will grow from one cell. Only five of them are for the development of the fetus and the umbilical cord, and fifty-three for nutrition. The emerging embryo is tiny, its height is 0.14 mm.

The appearance of a blastocyst is a vesicle filled with fluid. Growing up, it destroys the amniotic membrane, contributes to the rapid increase and weight gain of the embryo.

They are marked by a forty-hour process of transition and penetration into the uterine membrane. During implantation (attachment) of the embryo to the wall of the uterus, the expectant mother is disturbed by slight discharge with blood. They are physiological, disappear without treatment. The body is given a signal about the onset of pregnancy and a restructuring program is launched.

The embryo has completely penetrated the inner lining of the uterus (endometrium). He begins to receive the substances necessary for development through the mother's blood.

Days 9 - 14, 15 – 21 . Week two - three

The umbilical cord, placenta, neural tube (necessary for the formation of the nervous system) develops.
This is a very important stage in laying the foundation for future organs and systems of a new organism.
The baby's heartbeat appears.

Days 22 - 25. Week four

There are rudiments of the brain, heart, lungs, pancreas, liver. There is a chord (future spine). Foundation for the development of arms and legs. The formation of the neural tube is completed, for its proper formation, a sufficient intake of folic acid by a woman is necessary.
In the presence of various abnormalities (genetic diseases, a defect in the sperm or egg), right now the embryo may die.
Month two. Development of all vital organs.

Days 29 - 35. Week five

The beginning of the formation of systems and organs:

Digestion is represented by the pancreas and liver.
Respiration: larynx, trachea, lungs.
Hematopoietic system.
Sense organs (inner ear, eyes, which are originally located on the sides of the head).
Nervous system: formation of brain regions.
Reproductive system: the emergence of prototypes of future germ cells.
Musculoskeletal system: development of arms and legs, appearance of nail plates.
The development of the umbilical cord (it is still barely noticeable).

The weight of the embryo in this period of development is 0.4 grams.

Days 36 - 42. Week six

The placenta is formed, but its blood circulation with the embryo is still absent.
The brain is more developed. You can fix its signals during the encephalogram.
Facial muscles are present. The eyes are prominent, but the eyelids are absent.
The arms are elongated, brushes and fingers are formed on them.
There are cameras in the little heart.
There are kidneys, the beginning of the ureters.
Enzyme-producing organs (liver, pancreas) have developed sufficiently.
The stomach and all parts of the intestine are formed.

Days 43 - 49. Week seven

The formation of the umbilical cord is completed, the blood vessels of the child's place (placenta) and the umbilical cord are busy providing food and air. The production of the necessary hormones has been launched. The expectant mother has breast enlargement.
Half of the body is the head.
There is a small tail in the pelvis.
The fingers are not yet separated, but well formed.
Can move his hands, however, so far spontaneously.
The mouth opens. The eyes have eyelids that protect against overdrying.
Rudiments of ears, nasal passages.

Days 50 - 56. Week eight

The significantly grown body of the embryo is straightened.
At this stage, the face is very similar to a human, a little underdeveloped, but the eyes, nose, and lips are quite distinguishable.
In males, testicles are improved.
The fingers and toes are beautiful, without a skin partition.
The head, arms and legs grow faster, ossification of some bones begins.

The growth of the embryo on the fifty-sixth day of development is 20-21 mm.

So two months have passed, and we see a picture of the development of the embryo. All the organs necessary for life are formed, that is, the first stage of development of the future little man is behind.

Days 64 - 70.

The tail disappears, the buttocks are formed.
The respiratory system begins with the nose and ends with the lungs, ready for independent work.
The movements are no longer chaotic, but occur in response to irritation. For example: by touching the uterus, the child can bend or unbend the arm or leg, turn his head. The mother does not yet feel such movements due to the small size of the fetus (height 35-40 mm).

Important! Do not drink alcohol, drugs, toxins, so as not to harm the health of the baby, because the placenta does not yet fulfill its protective function.

Days 71 - 77.

The color of the eyes is determined, there is an iris.
The head is big. The legs are short, pulled up to the tummy. The arms are long.
During these days of development, the hormones produced in the body of a woman have an effect on the temperature regime. They also cause a deterioration in well-being (dizziness, weakness, pressure surges, a feeling of stuffiness, nausea).

Days 78 - 84.

White blood cells appear in the blood.

month four

Days 85 - 91.

The formation of organs is completed.
There is a lack of calcium due to the active growth of the baby's skeleton. Mom needs medications that replenish the volume of this microelement.

Days 92 - 98.

There are eyebrows, eyelashes, the first facial movements.
A heartbeat is heard through an obstetric stethoscope.

Days 99 - 105.

The pancreas produces one of the most important hormones - insulin.
Gender is formed.

Days 106 - 112.

Completion of the formation of fingers and nails. When examined on an ultrasound machine, we see a baby sucking a finger.
The child distinguishes between smell and taste.

Month five. First stir

Days 113 - 119.

Development of future teeth.
The emergence of hearing. Moves with loud noises.

Month seven. Preparing for the first breath.

Days 169 - 196.

Alveoli appeared in the lungs, they look like deflated balloons. They will deal with the first breath of the baby. At week 25, the alveoli produce a special substance (surfactant) to support their shape.
In boys, the testicles descend into their proper place (the scrotum).
In girls, the vagina, external genitalia, is formed.
The activity of the brain increases.

Month eight. Improvement of all organs and systems.

Days 197 - 224.

The child turns upside down, but there is a presentation (gluteal, transverse).
Organs and systems mature, preparing for independent work outside the mother's womb.
The pupils dilate and constrict, depending on the intensity of the light.
The brain is 25% the size of an adult.
The pushes are stronger, the movements are faster.
Increase in body weight by 25-35 grams per day.
A hormone is released that promotes milk production in the mother's breasts.

If the child was born 8 months old, he is quite viable, but needs special care.

Month ninth. Preparing for the birth

Days 225 - 252.

Thanks to the fontanelles, the bones of the child's skull are mobile and soft. This makes it easier for the head to pass through the birth canal.
The child is fixed in the uterus, as a rule, head down, there are practically no turns at this interval.

Month ten. Preparing for birth

Days 253 - 280.
A child weighing under 3-3.5 kilograms, height is about 0.50 meters. Everything is ready for the appearance in our world and further independent life, development in the womb is completed.

A few days will pass, and the mother will be able to hug and kiss her baby!

The stages of development of a child in the mother's womb are called trimesters, each of which is marked by intense transformations in the body of the fetus and its structure. The duration of the trimester is 90 days. During this time, the child manages to reach a new level of development. Consider the development of a child in the womb and their key features by week.

The development of a child in the womb on the example of a mannequin

Baby development in the first trimester

The first trimester of pregnancy begins at conception and lasts up to 15 weeks on average.

Week 1. The body is preparing for future motherhood. The body actively creates conditions for the most comfortable conception, and a little later - the development of the child in the womb of his mother. In the next two weeks, the body will need to form a prototype of the unborn child.

The structure of the genital organs and the conception of a child

Tips: if possible, refuse to take medications, with the exception of those prescribed by the doctor, and gradually accustom yourself to a healthy lifestyle - with regular walks, moderate physical activity, proper nutrition.

Smoking, alcohol and coffee starting from this period must be abandoned. Additionally, to prevent the development of fetal malformations, pregnant women are advised to drink folic acid regularly.

First week after conception

2 weeks. Changes in the reproductive organs of a woman become more obvious, a slight pulling pain may appear in the lower abdomen. The hormonal background begins to change under the influence of the developing corpus luteum. The egg is still preparing for fertilization.

Tips: The period from the end of the second week to the beginning of the third is ideal for subsequent conception.

Phases of the menstrual cycle favorable for conception

In order for the likelihood of pregnancy to be higher, a few days before the onset of ovulation, it is best to take a short break in sexual activity - this will allow sperm to accumulate.

3 weeks. During this period, conception itself occurs. Changes affecting the body of the expectant mother become even more pronounced.

Tips: for the safety of the child by these weeks, it is best to minimize contact with aggressive chemicals, sources of electromagnetic exposure. Avoid x-ray examination of the abdominal cavity.

4 weeks. During this period, implantation occurs. The woman also stops menstruating. The body of the child does not yet have a distinct outline and rather resembles a disk of three layers of tissues, from which the skin, skeleton, internal organs, etc. will subsequently develop.

5 weeks - photo and ultrasound

Tips: during this period, it is extremely important to protect yourself from overheating. An increase in temperature can have an extremely negative impact on the health of the unborn child.

5 week. The development of the embryo occurs intensively, due to which the outlines of the body, well-marked limbs are formed in the child, and the head stands out. The foundations of the future nervous system are being laid.

Tips: For better development of the baby's nervous system, mothers are advised to take folic acid.

Folic acid reduces the risk of miscarriage

Also, during this period, pregnant women need healthy sleep and rest more than ever - due to ongoing hormonal changes, she may begin to feel symptoms such as increased fatigue and irritability.

6 week. The child's brain is improving; he begins to gradually coordinate the work of the heart and skeletal muscles. Blood cells begin to form in the liver. The child already has the rudiments of most of the internal organs. The placenta grows, providing the baby with the nutrients necessary for growth and development.

Tips: during this period, dizziness and toxicosis may increase. In order for the unpleasant symptoms not to bother the woman so much, it is recommended to always have some salty crackers and water or juice with you (this will relieve nausea).

7 week. The features of the child's face become more distinguishable - he already has clearly visible auricles, jaws, eyelids, giving the child the opportunity to independently open and close his eyes. The child makes movements that are not yet felt by the mother, but are quite noticeable. The child's heart is already divided into 4 chambers, the largest blood vessels are formed.

7 week - the beginning of the formation of the body

Tips: for the full development of the child, a woman is recommended to eat foods rich in B vitamins. You can cope with toxicosis by eating often and in small portions.

8 week. The internal organs of the child are functioning quite actively - his heart is beating, the stomach and kidneys are actively working. The brain effectively organizes the activity of organ systems, the level of development of the nervous system already gives the child the opportunity to respond to their external conditions with the help of facial expressions. The skeleton is being improved - fingers and joints become clearly visible. The Rh factor of the child becomes clear.

Tips: you need to protect yourself from increased stress - both mental and physical. In order to better control the course of pregnancy, it is also desirable to find a doctor who will accompany the woman until delivery and give her valuable guidance.

9 week. This week is characterized by intensive development of the brain, especially the cerebellum, which is responsible for the coordination of movements. The child's eyes are already well formed, but covered with a membrane that does not allow them to see what is happening around. The limbs are strengthened. The fingers are already well distinguishable, but are interconnected by a membrane.

9 weeks - fingers appear

Tips: starting this week, you need to choose underwear that provides the body with proper support. It is best to reduce the load on the abdominal muscles. To prevent weakening of the veins, you can take preparations containing vitamins C and P.

10 week. During this period, the reproductive system of the child is most actively formed. The remaining vital organs are already well developed.

10 weeks - the body is fully formed

Tips: during this period, the mother needs foods rich in calcium - this will protect the bones and teeth from destruction.

11 week. At this time, the brain develops most actively and intensively: due to this, the head of the child is much larger than the body. The intestines and kidneys begin to work.

11 weeks - the baby begins to move

Tips: At this time, it is advisable to start saving money for the upcoming maternity leave. This will avoid many problems in the future.

Special care needs to be taken about the skin - it can become drier and begin to require more intense hydration.

Foods rich in calcium contribute to the proper development of the baby's skeleton

12 week. The child is already quite energetic - he actively interacts with the outside world and reacts to external stimuli - light, sound (for example, he can close his eyes with his palm, or cover his ears with his hands). A fairly good level of development of the cerebellum and the vestibular apparatus allows him to navigate well in space. Movements become more diverse: the child already knows how to make simple movements with his fingers, make head turns.

13 weeks - the brain is actively developing

Tips: if possible, it is necessary to avoid food poisoning, as well as conditions that provoke a state of hypoxia (intense physical exertion, hiking, etc.).

15 week - baby on ultrasound

Child development in the second trimester

Highlighting time intervals in development, we note that the stages of development of a small child in the womb of his mother are quite difficult to distinguish between weeks or months. However, from about 16 weeks, the second trimester of pregnancy begins, which has its own distinctive features.

16 weeks - photo

16 week. The child develops sucking and swallowing reflexes. His eyelashes and eyebrows are already clearly visible, he is learning to smile. The placenta, which connects mother and child, is already functioning quite actively. Growth is already 16-18 centimeters, weight - at least 150 g.

Tips: get tested for possible malformations of the child (recommended blood test for alpha protein, hCG hormone and unconjugated estriol). To improve the general condition of the body, you can go swimming.

20 weeks - the first portrait of the baby

20 week. The baby's heartbeat is already clearly audible with a stethoscope. Nails are formed on the fingers. Thanks to the good development of the musculoskeletal system, the child can already actively move inside the uterus and the woman already feels his movements inside herself. The child's reactions to light or sound become more diverse.

Swimming is very beneficial for pregnant women

Tips: It is very important to protect your back from unnecessary stress. Yoga, massage, physiotherapy exercises can help get rid of discomfort.

21 weeks - mom already feels the movements of the fetus

24 weeks. The child's lungs are actively developing, the sweat and sebaceous glands begin to work. the skin has a slightly reddish tint; amniotic fluid protects it from mechanical damage. The child's behavior also acquires new features - he can get angry and express his dissatisfaction, he can cry. Periods of wakefulness alternate with periods of sleep, and during the latter the child begins to dream.

Supportive underwear will help to avoid stretch marks

Tips: Due to the weakening of collagen fibers in the skin on the abdomen and chest, stretch marks can form. In order to avoid this, it is necessary to use a special intensively moisturizing cream.

Child development in the third trimester

The development of a child in the womb of his mother in the third trimester is different in that he has formed almost all vital organs and in the future they will have to actively develop.

28 week. All the senses of the child are already quite well developed. He begins to breathe on his own, the skin thickens. Weight approaches one kilogram. He begins to distinguish the voices of people and distinguish among them the voice of his mother.

28 weeks - the baby is fully formed

If we consider the development of the child in the womb of the child's mother by months, by this time the fetus reaches a 7-month period. If during this period the mother begins childbirth, he can survive thanks to the efforts of doctors and his own resources that ensure his life support.

Tips: during this period, you need to visit a doctor more often than before. In particular, among the necessary tests are the level of iron in the blood and glucose tolerance.

A premature baby can be born weighing up to 1 kg

In the event that both partners differ in positive Rh factors, another analysis will be required - for antibodies.

32 weeks. Due to the fact that the mother’s body actively transfers immunoglobulins to the child, immunity begins to form in him, which in the future can protect him from many health problems. Thanks to the already well-formed layer of subcutaneous adipose tissue, the child's body takes on a new shape. The amniotic fluid that surrounds the baby is renewed every three hours.

Gymnastics for pregnant women - preparation for childbirth

Tips: due to the fact that the child often rests his feet on the ribs, a woman may experience pain in the sternum. You can avoid this by trying to keep your back straight when walking and sitting.

34 weeks. The baby's lungs open and he can breathe on his own. With a height of 40 centimeters, his weight remains about 1700 - 2000 grams, and he continues to gain weight and this dynamics can be clearly seen by weeks. Because of this, he is already cramped in the uterus and he often takes the most convenient position for childbirth - head down.

Tips: during this period, the so-called Braxton-Hicks contractions, which are often confused with prenatal contractions, become quite frequent. In order to clearly distinguish them from each other, it is necessary to consult a doctor regularly.

The difference between false and true contractions

If water breaks, call a doctor immediately!

38 week. The child's liver intensively accumulates iron, which in the future will actively contribute to the hematopoietic function. It is growing rapidly, gaining at least 14 grams per day. The position of the child is determined finally. Development in the womb comes to its logical conclusion and the mother focuses on the birth of the child. He is ready for birth and only a few days remain until the moment of birth.

38 weeks - the baby is preparing for childbirth

Tips: you need to pay attention to the harbingers of childbirth - pain in the sciatic nerve and contractions.

Newborn baby - cutting the umbilical cord

Knowing the features that govern the development of a child in the womb of a woman by weeks and at each stage, you can prepare for each period of pregnancy, providing yourself and the child with everything you need. And at the same time - to create optimal conditions for healthy growth and development.

The development of the embryo (the germ of the unborn child) takes place in the best way in the mother's body. However, as part of the in vitro fertilization program, on which day the embryo is transferred to the uterus, it is determined individually in each individual case and depends on the quality of its development.

The day of egg collection from the female body by puncture is considered zero. On this day, a mature egg is fertilized with a sperm using standard IVF or ICSI.

1st day of development

On the first day, an analysis is carried out - fertilization has occurred or not. If the egg has two nuclei (pronuclei), we can talk about successful fertilization. In the future, pregnancy is possible. An embryo with one, three or more pronuclei, or without a nucleus at all, is discarded. Embryo transfer in the first day of development is practiced in very rare cases.

2nd day of development

On the second day of the development of a fertilized egg, when the female and male pronuclei have already merged (a zygote has formed), the first crushing has occurred, we can talk about a full-fledged embryo. Cells formed as a result of fragmentation of the embryo are called blastomeres. As a rule, on the second day of its development, the embryo consists of two to four blastomeres. At this stage, its quality can be assessed: by the volume occupied by non-nuclear fragments of the cytoplasm, that is, to determine the degree of fragmentation. The ability of the formed embryo to implantation and subsequent development depends on it. In addition to the degree of fragmentation of the embryo, its shape, as well as the size of the blastomeres, are also evaluated.

3rd day of development

On the third day of development, the embryo usually consists of six to eight blastomeres. However, four blastomeres are allowed in the case when on the second day of development the embryo consisted of two cells. Before the embryo reaches the eight-cell stage of its development, its cells are totipotent, that is, each blastomere is capable of giving rise to the development of a new individual organism. On the third day of development, the embryo includes its own genome, formed as a result of the fusion of male and female germ cells. Prior to this period, the development of the embryo proceeded, as it were, by inertia, on the “reserves” of the egg accumulated during its development in the ovary.

The further development of the embryo directly depends on which genome was formed and how successfully the switch to this genome took place. It is on the 3rd day of development that many embryos formed during the IVF program stop developing. The reason for this is errors in their genome, received by the embryo from parental gametes, or formed in the process of their fusion.

4th day of development

On the fourth day of development, an embryo of 8-16 cells is formed. At this stage, there is a compaction of intercellular contacts and smoothing of the surface of the embryo. Morula is formed. In the mother's body, it is at this stage that the embryo enters the uterine cavity from the fallopian tube. By the end of the fourth day of development, a cavity is observed in the morula, that is, the process of cavitation begins.

5-6th day of development

At the stage when the cavity inside the morula occupies half of its volume, the embryo is called a blastocyst. As a rule, the period of formation of the blastocyst falls on the fifth day of development, but it is also possible on the fourth or sixth days.

Blastocyst cells are represented by two populations:

a single-layer epithelium that surrounds the cavity - trophoblast;
internal dense lump of cell mass.

The blastocyst trophoblast is responsible for the process of implantation (implantation) of the embryo into the endometrium (uterine lining). In the future, trophoblast cells will give rise to the extraembryonic membranes of the fetus. The inner cell mass will give rise to all the organs and tissues of the unborn child. The better developed the cells of the blastocyst and the larger its cavity, the higher the potential of the embryo for successful implantation in the uterine epithelium.

At the moment when the blastocyst cavity reaches a large size, the zona pellucida is depleted due to its stretching, the process of hatching (hatching) of the embryo from the membrane begins. Only after this stage is completed is the blastocyst ready for implantation. The introduction of the embryo into the endometrium occurs, as a rule, on the sixth or seventh day of its development.

Only after implantation has occurred and the embryo has successfully settled in the uterus, we can talk about the onset of pregnancy as part of the in vitro fertilization program. In the future, doctors observe how the embryo develops over the weeks of pregnancy.

Pregnancy is only possible if a healthy embryo is used for implantation. Conception will not occur if a failure occurs at any stage in the development of the embryo. The mother's organism in this case will reject it. Successful implantation also depends on the individual characteristics of the body of each woman and the impact of external environmental factors and internal factors of the body.

How to behave as a woman after an embryo transfer

In the first days after the transfer of the embryo into the mother's body as part of the IVF program a woman needs:

limit physical activity, exclude the performance of strength exercises in the gym;
do not lift weights;
it is recommended to observe bed rest for the first day after the transfer;
do not take hot showers and baths;
avoid hypothermia;
refrain from driving;
healthy sleep for at least eight hours a day;
avoid nervous stress;
adhere to a balanced diet;
observe sexual rest.

Turning to the clinic "IVF Center" Volgograd, specialists in the field of reproduction and embryology will conduct a number of necessary tests, studies, answer all questions from patients and help solve the problem of infertility of each couple.