Where a child's fetus is born. How the fetus develops by week of pregnancy in pictures and description

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

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

Fetal development: stages and features

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

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

From one cell, trillions of new cells are formed in 38 weeks. There are more than 200 types of them, and they are 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 exhibits the first signs of pregnancy, when the process of fertilization of the egg occurs, its movement and fixation in the uterine cavity. During this period, the formation of the vital systems of the unborn child occurs. This trimester is considered very important for the fetus and mother, so a woman needs to take care of herself and take care of the health of her unborn baby.

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

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

Table 1

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

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

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

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

II trimester

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

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

table 2

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

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

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

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

III trimester

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

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

Table 3

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

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

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

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

After successful fertilization of the egg by the sperm in the uterus, a new organism begins to form, which after 40 weeks becomes a viable child, ready to be born. Pregnancy, as a physiological process, normally lasts 10 obstetric months, and the entire intrauterine period of fetal development It is customary to divide it into two stages: embryonic and fetal. At the stage of embryonic development - up to 8 weeks inclusive, the fertilized egg is considered an embryo and gradually begins to acquire human forms and features. From the 9th week until the birth of the child, doctors distinguish the fetal period of pregnancy, during which the embryo already becomes a fetus and goes through the process of forming its own systems and organs. The development of all vital internal organs of a child occurs at a specific time, which is subject to the genetic code embedded in the process of human evolution into reproductive cells.

Embryonic stage of development

First obstetric month

1 Week. From the moment of connection of healthy male and female cells - sperm and egg, fertilization occurs in the ampullary section of the fallopian tube. Over the next few hours, the active process of dividing the fertilized egg begins, during which it begins to gradually move into the uterine cavity down the fallopian tube. On average, a fertilized egg - a fertilized and multiplied egg - reaches the uterine cavity in 5 days. After the egg divides exponentially, it begins to look like a blackberry. It is worth noting that in Latin this berry is called “morus”, which is why the multicellular organism formed after cell division is commonly called morula in medicine.

By the end of the week, the morula should join one of the walls of the uterus - undergo an implantation process, during which the external cells of the embryo are embedded with their villi into the blood vessels of the organ. After the fusion of the morula with the female body, placental tissue begins to form, which subsequently forms a protective shell for the fetus, providing its nutrition until birth. Cells of the embryo that do not take part in the formation of cells for the placenta give impetus to the development of other membranes and the umbilical cord. The internal cells of the embryo, thanks to reunification with the mother’s body, after some time begin to lay the foundation for their own internal organs and systems.

2 weeks pregnant. After successful fusion with the mother’s body and the beginning of the formation of placental tissue, umbilical cord and other membranes, the embryo is even more intensively implanted into the uterine mucosa. Over the next seven days there will be active cell development for the umbilical cord and placenta, in addition, the foundation is laid for an important system of the unborn child - the neural tube, from which the brain and the entire nervous system of the new organism will then begin to form.

3 weeks pregnant. Days 15-21 of pregnancy are considered the most dangerous period - occurs complex process of laying down all important systems and organs future child. The digestive, respiratory, circulatory, nervous and excretory systems “lay down” the first rudiments in the embryo, and a wide plate appears in the place where its head will form. Based on this element and the neural tube, the brain will later form. By the 21st day, the cardiac tissue is so developed that it can provide a heartbeat.

4th week of development. Until the 28th day of pregnancy inclusive, continues formation of the foundations for all internal organs future child. It is completely natural for the embryo to develop the rudiments of the intestines, liver, lungs and kidneys by this time. Its small heart gradually increases its pumping intensity, pumping more and more of the embryo's blood through its circulatory system. It is worth noting that it is at the 4th week of development that the embryo acquires clearer outlines, reminiscent of a human torso, since its spine has already begun to form. The neural tube completes its development stage before day 25, and on day 28 after conception, muscles develop, forming the future muscular system. During this period, the embryo's spine is so strong that it divides its torso into two equal parts, and also gives impetus to the formation of the lower and upper limbs. In the area of ​​the unborn child's head, pits are formed that will become the basis of the fetal eyes.

Interesting: If you are interested in more detailed information about the weeks of pregnancy, you can use the full pregnancy calendar.

Second obstetric month

5th week of fetal development. By the 35th day of development, the embryo grows to 1.5-2.5 millimeters in length and weighs about 0.4 grams. This week, the constituent elements of systems such as the respiratory, digestive, reproductive and nervous systems are actively being formed. The embryo develops the rudiments of the liver, pancreas, larynx, trachea and lungs. Special cells are formed, a kind of precursors of germ cells. In the pits on the head the process of formation of the eyeballs and inner ear begins, and most parts of the future brain are actively formed. In the second month of pregnancy, the formation of the umbilical cord is more active, and it can already be distinguished. In general, the limbs of the embryo become more pronounced and acquire the basics of future nails. In the area of ​​the child's face, the outline of the upper lip differs, and the nasal cavities are formed.

6th week of pregnancy. From the 36th day of pregnancy, the embryo already has a body length of 4-5 millimeters. During this period, the tissues of the future placenta already form a pronounced membrane for the baby. At this stage of fetal development, the placenta gradually establishes fusion with the blood vessels of the female body, but blood circulation between the embryo and the mother is not yet functioning. Sections of the brain continue to take on clear forms, and doctors can already record the first signs of brain activity of the unborn child. When conducting an encephalogram during a routine examination, the child’s brain signals are already clearly recorded by the device.

The face of the unborn child gradually acquires its first features, since it is already facial muscles are formed. On the upper limbs, which noticeably elongate in length, the outlines of fingers and hands are formed. It is worth noting that the lower limbs at this time are still in their infancy. The embryo’s heart takes on a clearer shape, is divided into chambers (atria and ventricles), and the baby’s “primary” kidneys also begin to form, on the basis of which the ureters begin to grow. The digestive system lays the foundation for the stomach, large and small intestines, and other important digestive organs - the liver and pancreas - gradually complete their formation.

7th week of fetal development. The uteroplacental communication between the embryo and the mother at this stage already becomes possible due to the final formation of the umbilical cord. At this stage of development, the life support of the fetus is provided by the placenta and umbilical cord, oxygen and nutrients enter the body of the unborn child through the blood vessels. The location of the embryo's body in the uterus has an arched shape, and a small tail can be seen in the lower part of the pelvis. The head of the unborn child corresponds in size to half the total size of the embryo. Normally it should grow to 13-15 millimeters. Active growth of the upper limbs continues, the fingers have a clear shape, but are still connected to each other. At this stage of his development, the child may make uncontrollable limb movements, especially under the influence of external stimuli. His eyelids are already formed and protect his eyes from drying out, in addition, the baby periodically opens his mouth. A nasal fold and nose begin to form on the head, and two small elevations are visible on the sides - the rudiments of future ears. The brain continues to actively form.

8 weeks pregnant. From 50 to 56 days of pregnancy, the unborn baby grows from 15 to 21 millimeters in length. Internal organs and systems continue to actively develop, the heart grows, the lungs enlarge, the urinary system appears, the embryo acquires characteristic genital organs - the boy develops testicles. The ears are actively developing. By the end of the 8th week, the baby’s face becomes more and more human-like - eyes cover their eyelids, the nose and ears are visible, and both lips have finally formed. Active growth of the entire head begins, and the arms and legs go through the stage of ossification, the bones of the skull are formed. The membrane of skin disappears between the fingers. This week the embryonic stage of development of the unborn child is completed, the embryo becomes a fetus and begins the fetal period of its development.

Fetal stage of development

Third obstetric month

9th week of fetal development. On the 57th day of development, the fetus reaches 22 millimeters in length, by the 63rd day the growth increases to 31 millimeters. At this time, the condition of the placental vessels improves, due to which metabolic processes between the fetus and mother become more intense. The bones and muscles of the unborn child are actively developing - the process of ossification occurs, development of joints on the fingers and toes. From this moment on, you can observe frequent body movements in the fetus, which can clench and unclench its fingers. He lowers his head and presses his chin hard to his chest. The cardiovascular system becomes more powerful - the heart beats at a speed of 150 beats per minute, intensively pumping blood, which so far consists only of red blood cells. In the brain of the unborn child, the sections become larger and the basis for the future cerebellum begins to develop. In the endocrine system of the fetus, the adrenal glands begin to produce the first important hormones. The cartilage tissue of the ears and larynx is actively forming, and the vocal cords are also developing.

10th week of fetal development. On the 64th day of pregnancy, the fetus grows to 40 millimeters, the outline of its buttocks forms, and its small tail disappears. There is still quite a lot of space for him in the uterine cavity, so he occupies a free, semi-bent position. The nervous system continues to develop intensively, and the fetus often makes reflexive body movements. For example, in contact with the uterine wall, he turns his head, straightens or bends his legs and arms to push to the side. The woman does not yet feel these movements, since the size of the fetus is too small. This week the sucking reflex appears, and the diaphragm completes its development.

11th week of fetal development. By the end of this stage, the length of the child from crown to tailbone reaches 5 centimeters. His torso is still out of proportion due to his large head, long arms and short legs. The fetus bends its limbs at all joints and presses them to the stomach. The development of the placenta is finally completed and the membrane fully performs all its functions, delivering the necessary amount of oxygen and nutrients to the child, while the vessels also remove metabolic products and carbon dioxide. The eyes form an iris that affects their color, the eyeball is able to rotate and the eyelid opens and closes.

12th week of fetal development. From 78 to 85 days of pregnancy, the fetus grows to 50-60 millimeters. The gender becomes clearly visible, since the genital organs actively develop only according to the male or female type. The digestive organs are improved: the intestines lengthen, twisting into loops. In addition, the intestines periodically begin to contract - peristalsis is formed. Now the baby in the womb can swallow amniotic fluid, thereby developing a swallowing reflex. His brain already exactly repeats the shape of an adult organ, has all sections and both hemispheres, but is still very small in size. The behavior of the fetus is now more varied - by sucking its fist, the baby satisfies its sucking reflex. Leukocytes are formed in the blood, and the chest makes breathing movements. By the end of the 12th week, eyelashes and eyebrows appear on the face, and the neck takes on noticeable shape.

Fourth obstetric month

13th week of fetal development. At the end of this week, the fetus already reaches 75 millimeters, the outlines of its body change, and now you can see a small person in it. The limbs become longer, the body is larger, and the head is more proportional - now it no longer looks so big. The digestive organs are actively improved - the rudiments of milk teeth are formed under the upper and lower jaw. The facial features are almost formed - the nose, eyes and ears have clear outlines, and the eyelids are completely closed.

14th week of pregnancy. From 92-98 days, the unborn child grows to 9 centimeters. His body continues to improve, and the proportions become more familiar to the human eye. The forehead, nose, cheeks and chin are clearly visible on the face. The first hairs appear on the head, the body is also covered with small hairs. These hairs are fluff, retain lubricant and perform a number of protective functions. During this period, bones actively harden and muscle tissue grows, the fetus becomes more mobile - it periodically bends, turns over and tries to make the first swimming movements. The organs of the genitourinary system are finishing their formation - the kidneys begin to secrete fluid(baby pees) entering the fetal fluid. The fetal endocrine system is actively completing its formation, after which the pancreas will begin to secrete insulin. Pituitary cells in the brain gradually begin to function. The genital organs of the fetus acquire a perfect appearance: the prostate gland of boys finishes forming, and in girls the ovaries migrate into the pelvic cavity. As a result, using ultrasound it becomes possible to determine the sex of the unborn child.

15th week of pregnancy. By the end of the week, on the 105th day of pregnancy, the unborn baby weighs approximately 75 grams and reaches a length of ≈ 10 centimeters. The growth process of the fetal limbs becomes more intense than the head, so the body is already relatively proportional. By the end of the fourth month of pregnancy, the unborn child already has its own blood type and Rh factor, its blood vessels lengthen and thicken their walls. Meconium (original fetal feces) begins to be periodically produced by the intestines and enters the fetal fluid. This process is provoked by the entry of fetal fluid into the body of the unborn child, while he makes reflexive swallowing movements. The fingers and toes begin to form, and the skin at the tips takes on a special pattern.

16th week of fetal development. The fetus already weighs about 100 grams, grows up to 12 centimeters and has all the organs and systems. The genitourinary system works regularly, the kidneys produce a certain amount of urine (urine) every hour. Blood vessels are visible through the skin because subcutaneous fat has not yet formed. The skin has a bright red tint, covered with vellus hairs and lubricant. Eyelashes and eyebrows become thicker, nails are actively forming and already cover the edge of the nail phalanx. The fetus begins to develop facial expressions - the facial muscles finish developing, so it periodically frowns and even smiles.

Fifth obstetric month

Week 17. By the 119th day of pregnancy, the fetus gains weight of ≈ 120-150 grams and reaches 15 centimeters in length. The skin is still quite thin, but subcutaneous fatty tissue is already beginning to form. Dentin forms on the rudiments of baby teeth, and permanent teeth form underneath them. The fetus can already react to sound with active movements, and some women, especially very sensitive ones, can feel these movements. The position of the unborn child in the uterus changes - it becomes vertical, the baby bends his arms at the elbow joints, and clenches his fingers into fists almost all the time. Unclenching his fists, the baby straightens his fingers and even sucks, often the big one. The heartbeat can already be clearly heard when examined by a gynecologist using a stethoscope.

18th week of pregnancy. The weight of the fetal body reaches 200 grams, and the length from the crown to the tailbone is 20 centimeters. This week, you can record a semblance of the sleep and wakefulness of the unborn child, who sleeps most of the time and makes active movements during the waking period. Most pregnant women begin to clearly feel movements and fetal movements. As a rule, you can feel gentle kicks of the unborn baby as it pushes away from the wall of the uterus or responds to sounds. The mother's stress also provokes the fetus to make movements. Normally, at this stage, the unborn child should make up to 10 episodes of movements during the day.

Week 19. On days 127-133 of pregnancy, the fetus weighs up to 300 grams, while growing to 22-23 centimeters. Its proportions change - the head grows much slower than the body, and the limbs continue to actively lengthen. The fetus often moves, its mother feels it, and others can even feel it by touching the belly. It is worth noting that at this stage during the first pregnancy, the woman may not yet recognize fetal movements, unlike a more experienced mother. The organs of the endocrine system of the unborn child work very actively, and the blood gradually acquires a new composition - monocytes and lymphocytes are added to erythrocytes and leukocytes. The spleen begins to take part in the formation of fetal blood cells.

Week 20. The body weight of the fetus on days 134-140 reaches 340 grams, and its length grows to 25 centimeters. The skin is still very thin, but the subcutaneous tissue has practically formed, and vellus hairs and lubricant protect the fetus. The eyes are already so formed that the baby has a blinking reflex. The coordination of the movements of the unborn child becomes more pronounced and active: the thumb is brought to the mouth with a conscious movement, the eyes may close, the lips may stretch into a smile and the eyebrows may frown. All expectant mothers, without exception, already clearly feel the movements of the child in the womb, noting changes in his movements during the day. The fetus becomes especially active under the influence of irritants - loud sounds or stuffiness.

Sixth obstetric month

21 weeks. At 141-147 days of pregnancy, the fetus already reaches 27 centimeters in length and weighs about 380 grams. His skin acquires folds and becomes wrinkled due to the dense layer of subcutaneous tissue. The fetus moves more and more often, moves freely in the uterus, can be positioned upside down or upside down, and sometimes lies across the uterus. Thanks to its developed arms, the unborn child periodically grabs the umbilical cord, and with its legs it can decisively push off from the uterine wall. His sleep and wakefulness patterns change - less time is devoted to sleep.

22 week of fetal development. During days 148-154 of pregnancy, the fetus increases in size to 28 centimeters and weighs about 500 grams. The body of the unborn child becomes more proportional - the head is no longer so large relative to the whole body. His legs are almost always bent at the hip and knee joints. The bones continue to actively strengthen. The spine is almost completely formed and has all the joints, vertebrae and ligaments. All the nerve cells - neurons - have appeared in the brain, and the organ weighs approximately 100 grams. The fetus becomes more conscious - it is interested in its own body, touching its face, arms and legs, while it deliberately tilts its head and brings its hands to its face. His heart enlarges and improves its work.

23 weeks pregnant. At this stage of fetal development, the body reaches 30 centimeters in length and weighs 500 grams. At week 23, the skin already acquires a bright color - red, due to the synthesis of a special pigment, but the subcutaneous fatty tissue is still thin, so the fetal body looks thin and wrinkled. The entire skin of the unborn child is covered with a thick layer of lubricant that gets into the folds of the body. The genital organs continue to develop and the activity of the diaphragm increases. The fetus can make respiratory movements 50-60 times per minute and constantly swallows amniotic fluid along with the protective lubricant of the skin. As a result, these substances enter the intestines and turn into meconium, which normally should not leave the body until childbirth. The swallowing reflex and the entry of liquid into the baby’s intestines provokes hiccups, which are easily felt by the expectant mother.

Week 24. On the 168th day of its development, the fetus reaches 32 centimeters in length and weighs approximately 600 grams. It begins to move even more actively in the womb and gradually occupies almost the entire uterine cavity. At the same time, the baby sometimes changes its position and even turns over, which is facilitated by active muscle growth. It can be noted that at the 24th week of pregnancy, the unborn child already has developed sensory organs: the eyes begin to function fully, therefore, when bright light hits the pregnant woman’s belly, the fetus turns away from it or closes its eyelids. The hearing organs are also well developed and functioning, so the fetus distinguishes the voice of its mother and actively reacts to unpleasant or loud sounds. At this stage, a strong emotional connection is established between the fetus and the woman, so the child also begins to experience any negative emotions of the mother with her.

Seventh obstetric month

25 week of fetal development. By the 175th day of the period, the weight of the fetus is approximately 650-700 grams, and the length is 30-34 centimeters. The child’s skin becomes elastic, folds become less noticeable, as the layer of fatty tissue increases. In the still thin skin, a large number of capillaries are formed, giving it a bright red tint. The facial part of the head becomes more similar to the face of an adult: the eyes are clearly defined, framed by eyelashes and eyebrows, and on ultrasound the cheeks of the unborn child and the outlines of the ears are already visible. The curves and curls of the ears have not yet fully formed; the cartilage has a soft and thin structure. Active development of the bone marrow occurs, due to which the process of hematopoiesis is enhanced and the bones are strengthened. Tissues mature in the lungs - alveoli are formed, but until the birth of the baby, the organ will be without air. In their shape, the alveoli still resemble deflated balloons, which will expand after the child’s first breath. At the 25th week of pregnancy, the alveoli already produce a special element - surfactant, which ensures their shape.

Week 26. This week, the unborn child increases to 35 centimeters in length, gaining a weight of 750-760 grams. Its fatty tissue and muscle tissue are actively gaining volume, and the main teeth also continue to form. The genitals in boys are already beginning to descend into the scrotum, and this process will last about 4 weeks, while in girls at this time the outlines of the external genitalia are forming. Sense organs are increasingly improved, so the fetus sometimes distinguishes odors.

Week 27. On days 183-189 of pregnancy, the weight of the unborn child increases to 850 grams with a height of 37 centimeters. The active process of activity of the fetal endocrine system begins - the pituitary gland, pancreas and thyroid gland perform the necessary functions. The unborn baby often moves its limbs and head, freely changing its location in the uterine cavity. From this moment the process of formation of his personal metabolism begins.

Week 28. The body weight of the unborn child reaches 950 grams, and the length is 38 centimeters. At this stage of formation, the fetus can be considered viable, but only in the absence of pathologies of internal organs. The fatty tissue continues to increase in volume, but the skin is still red. The skin gradually gets rid of vellus hairs, which are partially retained on the shoulders and back. The hairs of the eyebrows and eyelashes acquire a more intense shade, and the amount of dark hair on the head also increases. Periodically, the unborn child opens his eyelids, his nose and ears remain soft, but his nails already cover half of the phalanx of his fingers. From this moment on, one of the cerebral hemispheres may begin to actively work. Interesting fact: with an active right hemisphere, the unborn child will become left-handed, with the left hemisphere - right-handed.

Eighth obstetric month

Week 29. From 197 to 203 days of pregnancy, the unborn child is actively gaining body weight and weighs approximately 1200 grams with a height of 39 centimeters. The fetal body has grown so much that it occupies almost the entire uterine cavity, so chaotic and frequent body movements are already excluded. The fetus occasionally moves gently, making points with its hands or feet to take a specific position in the uterus for future birth. Normally, he should lower himself to the pharynx with his head or pelvis. In general, all internal organs and systems continue to develop; for example, the kidneys already secrete 500 milliliters of urine per day. The cardiovascular system increases the load, but its blood circulation is still different from that of an adult.

30th week of pregnancy. From 204 to 210 days of pregnancy, the unborn child gains weight up to 1300-1350 grams with a height of 39 centimeters. The layer of subcutaneous fatty tissue actively accumulates, straightening the folds, and the child himself begins to gradually adapt to the limited space in the uterus. As a rule, he already takes a certain and comfortable position for himself - he curls up and crosses his limbs. Even though the vellus hairs and grease are gradually disappearing from his skin, it (the skin) still remains red in color. Alveoli are actively formed in the lungs and surfactant is produced, thereby preparing the respiratory organs for childbirth. The brain enlarges due to the formation of new convolutions and expansion of the cortex area.

31 weeks. Days 211-217 of pregnancy are characterized by an increase in fetal body weight to 1500-1700 grams with a height of 40 centimeters. Changes occur in the sleep and rest mode: sleep takes up most of the time of the day, but while awake, the child actively moves and pushes the mother’s belly with his legs. You may notice frequent blinking of the eyelids and a change in the color of the iris to blue. The pupils of the unborn child are already fully formed and react by constriction to bright light. The volume of the brain reaches 25% of the size of the adult brain.

Week 32. At this stage of the period, the fetus gains a mass of 1700-1800 grams and grows to 42 centimeters. The skin gradually lightens and gets rid of wrinkles due to an increase in fatty tissue. Internal organs are actively improving, the endocrine system produces hormones, and the lungs accumulate a sufficient amount of surfactant. Thanks to a special hormone, this week the mammary glands in a woman’s body begin to prepare to produce milk for the baby.

Ninth obstetric month

Week 33. At 225-231 days of age, the fetus weighs approximately 2 kilograms and grows 43-44 centimeters. The skin becomes lighter and smoother under the influence of fatty tissue. The vellus hairs almost completely disappear, but the layer of protective lubricant becomes denser. The nail plate strengthens and covers the entire phalanx of the finger. The unborn child moves very rarely, but at the same time makes strong pushes, since he no longer has enough space to move freely. Its location relative to the pharynx of the womb is finally fixed and from this moment on, the chances that it will change its position decrease. Internal organs increase the intensity of work, the heart becomes larger, the alveoli have finished forming and vascular tone has appeared. The brain formed all the sections and the cortex.

34 week. From 232 to 238 days of pregnancy, the weight of the unborn child increases to 2500 grams with a height of 45 centimeters. At this stage of development, the fetus has soft skull bones due to the mobility of the fontanelles, which is necessary for delivery. The bones on the head will only become stronger a few months after the baby is born. Active growth of hair on the head continues, and it acquires a certain color, which may change after childbirth. The bones of the body actively increase and strengthen, for which the child’s body takes calcium and other substances from the mother’s body. The fetus continues to actively swallow amniotic fluid, which stimulates its production of up to 600 milliliters of urine per day.

Week 35. On the 245th day of the term, the unborn child gains weight by about 35 grams every day, so the weight of the fetus can change greatly, and by the end of the week it can be 2200-2700 grams with a height of ≈ 46 centimeters. The body of the unborn child is actively preparing for childbirth, strengthening internal organs, increasing the volume of fatty tissue and getting rid of vellus hairs. The fingernails had finally formed, and a large amount of meconium had accumulated in the intestines.

Week 36. From days 246 to 252, the child gains from 2 to 3 kilograms of weight with a height of 46-48 centimeters. The skin becomes light in color, fatty tissue has formed and folds have completely disappeared. Often, the fetus in the womb is positioned upside down, bent and leaning it against the chest, and the limbs are crossed and pressed to the body. Almost all the bones, except the skull, are already strong, and the internal organs are ready for extrauterine life.

Tenth obstetric month

Week 37. By the 259th day of pregnancy, the unborn baby may gain different body weight, depending on genetic disposition, but its height should be approximately 49 centimeters. The skin actively thickens, and fatty tissue gains up to 14-15 grams of volume per day. The cartilages of the nose and ears are also actively compacting, the lungs are already mature, and a sufficient amount of surfactant has accumulated in the alveoli. The digestive organs have finished forming, and the stomach and intestines can periodically contract to push food through.

38 week of fetal development. Days 260-266 are characterized by an increase in fetal body weight, which often varies. At the same time, the unborn child is already completely ready for childbirth and life outside the womb. His appearance completely corresponds to that of a normal child: the skin is of a natural color, there is sufficient fatty tissue, and the vellus hair has completely disappeared.

39 weeks pregnant. On days 267-273 of pregnancy, the fetus should begin to gradually descend towards the os of the uterus - towards the birth canal. Usually it is pressed against the mother’s pelvic bones, and the placenta gradually ages, no longer ensuring the normal course of all metabolic processes between the child and the mother. Normally, the fetus should reach absolute maturity, but at the same time it still gains 35 grams of weight per day. The proportions of his body have been completely modified: the chest and shoulder girdle are well developed, the stomach has become rounded, and the limbs have lengthened.

Week 40 (Childbirth). On the 274-280th day of the term, the child should be born, since it has already achieved compliance with the shape and condition of the newborn. Its body weight can vary from 2.5 to 4 kilograms. From this week, the expectant mother should expect the appearance of uterine contractions - the beginning of labor. In this case, the baby’s head, with the soft bones of the skull, should press closely to the pelvic cavity and prepare for passage through the birth canal.

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

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

Obstetric and embryonic periods differ:

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

1 Week

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

Happens:

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

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

2nd week

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

Child development:

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

For a woman:

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

3rd week

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

Child development:

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

The expectant mother is worried about:

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

4th week

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

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

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

At this stage the baby experiences:

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

5th week

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

Child characteristics:

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

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

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

6th week

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

Fetus:

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

Feelings of a young mother:

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

7th week

Mid-first trimester of pregnancy.

Child development:

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

Woman's well-being:

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

8th week

Pregnancy lasts about 2 months.

Baby changes:

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

For a pregnant woman:

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

9th week

Baby:

Future mom:

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

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

Week 10

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

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

The young mother's condition worsens due to:

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

Week 11

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

Child's condition:

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

Maternal body:

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

12-week

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

Fully formed:

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

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

Week 13

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

The baby during this period:

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

The young mother feels:

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

2nd trimester: 14 – 27 weeks of pregnancy

How the fetus develops over the weeks of pregnancy in the second trimester depends on the health status of the expectant mother. During this period, bone tissue is formed and the baby is nourished from the resources of the mother’s body.

Week 14

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

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

The following are fully operational:

• spleen;
• liver;
• pancreas.

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

Week 15

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

During this week, a woman:

Child development:

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

Week 16

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

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

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

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

Week 17

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

Characterized by:

A woman's condition is determined by:

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

Week 18

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

For a young mother, this period is accompanied by:

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

Week 19

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

Week 20

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

21st week

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

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

Week 22

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

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

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

Week 23

The woman's condition is satisfactory.

Characteristic features of the period:

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

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

Week 24

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

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

Week 25

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

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

Week 26

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

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

Week 27

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

3rd trimester: 28 – 36 weeks of pregnancy

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

28 week

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

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

Week 29

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

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

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

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

• adrenal glands;
• body temperature regulator.

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

30th week

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

31st week

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

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

Week 32

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

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

Week 33

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

Week 34

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

Week 35

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

36 – 37 weeks of pregnancy

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

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

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

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

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

38-40 weeks of pregnancy

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

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

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

41-42 weeks of pregnancy

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

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

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

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

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

Article format: Svetlana Ovsyanikova

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

How the fetus develops by week of pregnancy:

Fetal development at 11 weeks of gestation:

The gestation period is not calculated in months; for convenience, gynecologists adhere to the obstetric method of calculating the gestation period by week. The first week is the most mysterious of all the upcoming ones. Its calculation is made by the gynecologist purely theoretically, based on the calculation of the first days of the cycle and the estimated day of ovulation.

In medicine, the countdown is from the first to the last menstruation. This is due to the fact that it is quite difficult to determine the exact day of conception - for each woman, ovulation occurs on different days of the cycle, depending on its duration and the physiological characteristics of the expectant mother. For this reason, gynecologists always focus on the obstetric period, and not the embryonic period.

A normal pregnancy lasts 40 obstetric weeks, 280 days or 10 lunar months.

From a scientific point of view, in the first week of pregnancy, the follicle matures - a fluid-filled sac in which the egg is located. After emerging from the shell, it lives from 24 to 48 hours. The inner layer of the follicle walls produces estrogen hormones, which contribute to the restoration and growth of the mucous layer in the uterus, preparing its cavity for the upcoming pregnancy.

Are you wondering what rules you need to follow during each week of pregnancy?

We invite you to familiarize yourself with the detailed pregnancy calendar on our website, which describes in detail what happens with the formation of the fetus at each of the 42 weeks -.

Over time, the egg will be fertilized by a sperm. After the fusion of cells occurs, they begin to divide and the zygote from the fallopian tube enters the uterine cavity. This is a special cell - it stores the genetic material of the father and mother. The unborn child will acquire genetic characteristics from both parents.

Implantation takes place within 7 days. In the uterus, the zygote will attach to the wall and in the new house will begin to develop further, gradually turning into a little person.

The embryonic period is the most important. The woman does not yet suspect pregnancy, and the embryo goes through successive stages of development. At this time, one or more fetuses are determined to develop in the uterus and a chorion is formed, which participates in the formation of the placenta.

Symptoms and sensations in the early stages

1 week of pregnancy coincides with the beginning of the menstrual cycle. The muscles of the uterus contract, expelling the rejected endometrial layer, and the woman’s well-being improves.

At this stage, the woman knows nothing about her “interesting” situation. Accordingly, all symptoms and signs are still absent - the mammary glands do not swell, there is no toxicosis, fatigue and odor intolerance. During this period, the nature of vaginal discharge changes slightly, which is considered normal.

Pregnancy cannot be determined by donating blood to check the hCG level. The test will not show any changes - if the body is healthy and there are no hormonal imbalances, only one strip will appear on it.

There are a number of symptoms that women rarely experience at 1 week:

• mucous discharge with thin blood streaks, as evidence of embryo attachment;
• stretching and pressure in the pubic area;
• denial of smoking and alcohol is a protective reaction of the body on a subconscious level;
• emotional instability.

In the first week of pregnancy, fatigue increases. A woman gets tired faster and cannot cope with normal physical activity. It’s as if the body is switching on “delicate mode” and trying to maintain strength.

Not all expectant mothers exhibit such symptoms; they can only be noticed if you constantly listen to your own body.

It is impossible to confirm 1 week of pregnancy, despite all the achievements of modern medicine. All that remains is to wait until characteristic signs appear. No gynecologist will be able to determine the onset of pregnancy in the first week.

Video - pregnancy symptoms

Changes in the mother's body at 1 week of pregnancy

Immediately after conception, the female body begins a global restructuring, trying to provide itself and the emerging embryo with everything necessary.

1. The release of large amounts of estrogen can affect the mammary glands. They increase in size, the nipple halos become darker and swell. The chest becomes painful.
2. Changes occur in the central nervous system. The influence of the vagus nerve increases and the expectant mother becomes inattentive, absent-minded, taste perception changes, and salivation increases. Weakness and dizziness become a frequent companion.
3. The restructuring of the circulatory system begins: uterine blood flow increases, the volume of circulating blood increases. A woman’s body tries to adjust to its ability to supply a sufficient amount of oxygen to the fetus.
4. The basal temperature changes, and if this method of ovulation control is used during planning, the expectant mother will learn about the onset of pregnancy at a very early stage.

Nausea and vomiting appear much later. If you experience bouts of toxicosis in the mornings or evenings, you may already be a little longer than you think.

What happens to the fetus at 1 week of pregnancy

The fusion of the egg released from the follicle with the sperm symbolizes the birth of a new life. This is just one cell that has to go through a huge development path in the womb.

From the moment of fertilization, active cell division occurs in the zygote, which from the unorganized mass forms a hollow ball - a blastocyst.

Despite the fact that the size of the embryo is now only 0.2 mm, the sex of the unborn child has already been determined - it depends on the X or Y sex chromosome received from the father. The rest of the chromosome set contains data in accordance with which all systems and organs of the fetus will develop.

The outer layer of the blastocyst, penetrating into the walls of the uterus, begins to synthesize the pregnancy hormone - human chorionic gonadotropin. The level of hCG determines the onset of pregnancy in the early stages; this is one of the most reliable indicators.

Diet

The menu of a woman planning to become a mother differs from the usual diet. Nutrition should be complete and balanced, rich in protein and moderate amounts of fat.

A third of the total diet should be fresh vegetables and fruits, raw or thermally processed. Be sure to eat fatty fish, which has great benefits for the brain.

Obstetrician-gynecologists and nutritionists give some nutritional recommendations to expectant mothers in the 1st week of pregnancy.

Vitamins and minerals, if they are lacking in foods, should be taken in separate complexes. This will reduce the risk of defects during fetal development caused by a deficiency of nutrients.

Special attention should be paid to vitamin B9, or folic acid. It is able to reduce the negative impact of external and hereditary factors on the embryo, and have a beneficial effect on the formation of the nervous system and the general condition of the fetus.

Other vitamin preparations will be prescribed by the doctor after examination, test results and registration.

During the first week of pregnancy, it is highly not recommended to adhere to strict diets and strict dietary restrictions. If a pregnant woman is overweight, she should seek the help of a qualified nutritionist. The specialist will create a balanced menu individually, taking into account all the nuances.

Very often during pregnancy, a woman begins to eat for two. There is no need to do this! Overeating will only lead to excess weight. Extra pounds will harm the unborn child, and constant weight gain will negatively affect the health of the pregnant woman in the final stages.

Medical recommendations and advice on the lifestyle of the expectant mother at this stage

When expecting pregnancy, a woman should think about her lifestyle and adjust it according to the recommendations. Taking good care of yourself even before conception significantly increases your chances of bearing and giving birth to a healthy child.

1. Prepare mentally for the upcoming changes. Over the next 9 months, unusual processes will occur in your body, most of which are unpleasant. Toxicosis, abdominal pain, changes in figure, drowsiness and frequent urge to urinate are natural processes. Treat them with patience, without irritation. After all, in 39 weeks everything will be over and you will have your long-awaited baby in your arms.
2. Try to rest more and just sleep. Take some time to nap during the day and surround yourself with beautiful things.
3. Limit communication with unpleasant people, try to avoid conflicts and stressful situations at work and at home.
4. Avoid going to the sauna, bathhouse, and taking hot baths.
5. As soon as you find out that you are pregnant, go to the doctor immediately. A specialist will use an examination or ultrasound to confirm that there is a fertilized egg in the uterus and assess your general condition. If necessary, the gynecologist will prescribe maintenance medications and do everything necessary to maintain the pregnancy.
6. Take medications with caution, only as prescribed by your doctor. Treat a common cold with folk remedies, resorting to pharmacological drugs last. Avoid contact with sick people, do not visit crowded places during epidemics, beware of hypothermia.
7. Stop drinking alcohol, smoking and strong psychotropic drugs.
8. Extreme sports are no longer for you - take care of yourself and your unborn child. A sudden surge of adrenaline will not do you any good.
9. It is prohibited to be exposed to x-rays or undergo fluorography..

Dangers in 1 week of pregnancy

In the first week of pregnancy, spontaneous abortions often occur - miscarriages, which the woman does not even suspect, mistaking them for another menstruation.

Another danger is ectopic pregnancy. It occurs when, for some reason, a fertilized cell attaches to the fallopian tube or exits into the abdominal cavity. This condition threatens the woman’s life and requires surgical intervention. The first ultrasound is prescribed specifically to exclude improper attachment.

Chromosomal abnormalities are another cause of early self-abortions. The embryo stops developing, and the mother’s body rejects it.

Due to hormonal imbalances, inflammation of the endometrium, scars and synechiae in the uterine cavity, blastocyst implantation is difficult, the embryo dies and is removed during the next menstruation.

Risk factors include taking strong medications or antibacterial drugs. This leads to termination of pregnancy or to serious consequences for the fetus during its subsequent development.

Ultrasound of fetal development

In the first week of pregnancy, an ultrasound examination reveals a thickened layer of the endometrium in the uterine cavity, which is preparing for the attachment of a fertilized egg.

An examination of the ovaries is also carried out in order to determine in which of them the dominant follicle has matured. It looks like a round dark cavity and differs in size from others.

The ripening follicle has an irregular shape; an egg-bearing tubercle appears on it, which is the basis for the future egg.

The corpus luteum looks like a dark spot with irregular contours. It develops in the place where the follicle burst and produces progesterone.

Video - 1 week of pregnancy description, sensations, discharge, fetal development, photo and ultrasound

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From the moment a woman finds out about pregnancy, she begins to listen to her body every day, trying to catch the slightest changes and understand what is happening with the unborn child. If we are talking about in vitro fertilization, then increased attention to one’s feelings begins even earlier. How does the embryo develop week by week? Let us list the most characteristic processes at all stages of its development in vitro and in utero.

Photo of embryo development by day after IVF

Stages of embryo development

Back in the 1960s, photographer Lennart Nilsson, using a powerful lens, managed to take photos of the development of an embryo week by week. By and large, this process is the same both during natural conception and if in vitro fertilization was used. Only the initial stages of intrauterine development differ. We list the main stages of embryo development by week after IVF:

First trimester

The first trimester is the most important in the formation of the embryo, since it is during this period that the laying of organs occurs.

Second trimester

14-15 weeks. Eyebrows and eyelashes appear, the baby can make facial movements, and the musculoskeletal system is strengthened. The heartbeat becomes so loud that it can be heard using an obstetric stethoscope. The pancreas begins to produce insulin, the genital organs change (for example, in boys a prostate gland is formed).

16-19 weeks. Fingernails appear, sense organs improve, ears begin to hear, and eyes begin to discern light. The size of the fetus increases so much that the mother feels its movements; The composition of the blood becomes more perfect.

20-25 weeks. During this period, coordination of movements improves; All women begin to feel fetal movements. Bones are strengthened.

Third trimester

26-30 weeks. The formation of alveoli in the lungs ends, which produce the substance (surfactant) necessary to maintain their shape. The baby actively reacts to loud sounds and may blink. The brain develops rapidly, adipose tissue begins to form, and the skin becomes elastic. By this time, the child becomes practically viable.

30-38 weeks. The skin becomes smoother, the child gains weight, and the functioning of internal organs improves. Closer to the time of birth, the baby changes position, turning head down (not always, but in most cases).

Human fetal development

Fruit size chart

The weight and height of the fetus are one of the most important parameters that help determine how correctly its intrauterine development is proceeding. Ultrasound examination, as well as standard measurements of the size of the uterus and abdominal circumference, make it possible to track these criteria, with some acceptable errors. The table below shows the average values ​​that the doctor uses when assessing fetal development.

Typically, weight and height are measured starting from the second trimester, since in an earlier period it is quite difficult to do this due to the small size of the embryo. In many ways, these parameters are individual; they depend on heredity, the sex of the child and other factors, and the above data are indicative.