The process of giving birth to a new life can only be compared to magic. A woman feels such transformations only during a special period. Not only her body and feelings change, but also her awareness of the whole world. Together with the child, the expectant mother goes through a huge stage from the appearance of one cell to the birth of a new inhabitant of the planet.

Pregnancy week by week, the development of the fetus and the woman’s sensations will allow us to understand the changes that occur at the physiological and psychological level. The entire period will last 40 weeks, or 10 lunar months, each of which has 28 days (a full cycle).

1 week pregnant

According to obstetric terms, the first week is considered to be the last day of menstruation. Conception does not necessarily occur during this period; it can occur after 2 or 3 weeks, depending on the time of ovulation. You can find out about the onset of the long-awaited state only by measuring your basal temperature. At this time, home tests or blood donation for hCG will not show the true result. There are no obvious signs, the woman is still active, her body is still just going through the preparatory stages.

Fertilization

The fusion of the egg and sperm occurs in the fallopian tube. As soon as fertilization has occurred, one main cell is formed - the zygote. It is this that is the basis of all systems and organs that will be laid down and formed over the course of 9 months. The first violent chemical reactions begin, increased synthesis of special hCG hormones is observed on days 5-6. This will reduce the immune defense of the maternal body in order to preserve the embryo.

• get rid of bad habits, smoking, alcohol;
• start eating right; your body should receive proteins, fats and carbohydrates in a ratio of 1:1:4, respectively;
• Avoid medical procedures involving radiation; when taking medications, you should consult a doctor;
• You may need multivitamins that include folic acid; it is advisable for the expectant mother to start the course at the pre-planning stage.

The woman’s feelings are no different, she leads a normal lifestyle, physiological changes will come a little later. But some mothers, with very developed intuition and sensitivity, can determine the exact onset of conception without tests or analyses.

2 weeks pregnant

According to obstetric dates, this is the time of ovulation. During this period after the end of menstruation, the body is actively preparing for reproductive function. The ovaries release an egg, and if there are several, a multiple pregnancy can occur. Through the abdominal cavity it is sent to the fallopian tube, the whole process is controlled by the hypothalamus. The egg awaits conception throughout the day. The sperm has a higher viability up to 5 days.

The time of ovulation occurs in the middle of the cycle; if it consists of 28 days, then on the 14th day the egg matures. If conception does not happen, then after 2 weeks the unfertilized female cell is excreted during menstruation.

Woman's feelings:

• hormonal levels change, sensitivity to odors may appear;
• pulling sensations in the lower abdomen;
• increased libido, development of sensuality and sexuality.

You can calculate the moment of ovulation using special pharmacy tests, or by measuring basal temperature!

These are optional symptoms; more often than not, women do not notice such subtle processes that prepare her body for motherhood.

3 weeks pregnant

In fact, this is the first week of the birth of future life. Conception occurs as follows. The most active and strong sperm reach the egg 1-2 hours, the rest are destroyed by the protective cells of the female reproductive system. The egg is many times larger than the sperm and consists of several membranes. The strongest and fastest penetrates inside, and fusion begins, forming a unique set of chromosomes. The remaining sperm die.

The resulting zygote moves from the fallopian tube into the uterine cavity. At this time, it is nourished by protein compounds of tissues, as well as internal reserves. As soon as it is fixed on the walls of the uterus, the process of preparing the maternal body begins. Embryo implantation may be accompanied by scanty spotting, and sometimes a woman simply does not notice it.

A woman’s sensations depend on her sensitivity. Some experience nausea, weakness, and dizziness. The most important thing at this stage is to ensure sufficient intake of protein, folic acid, calcium and iron. Therefore, it is worth adjusting your diet and daily routine; overwork and stress can have a detrimental effect on the course of development.

4 weeks pregnant

During this period, the placenta and amniotic fluid begin to form, they will provide the baby with vital functions. In addition, the head appears, 3 main layers are also laid, after which systems and organs will develop. Paternal genes are responsible for their formation.

Appearance of the embryo:

• ectoderm – formation of the brain;
• endoderm – organs of the gastrointestinal tract, thyroid gland, liver;
• mesoderm – musculoskeletal and circulatory system.

Mom's feelings:

• there is a sharp change in mood, drowsiness, or vice versa – a surge of energy;
• increased irritability to smells and tastes;
• nausea in the morning, dizziness;
• The breasts may already become larger and the sensitivity of the nipples will increase.

Pregnancy can be determined using a test or ultrasound. During this period, it is necessary to provide adequate nutrition and a gentle regime. It is important to take care of your immunity, avoid attending public events and contact with sick people.

5th week of pregnancy

The expectant mother is already beginning to suspect a new condition, because menstruation should have happened a week ago. In addition to psycho-emotional moments, there are other signs of conception.

Physiological changes in a woman:

• the amount of discharge increases, normally it resembles mucus, like chicken protein, at this time a plug is formed that protects the fetus from infections until the moment of birth;
• heaviness and pain in the lower abdomen may signal the development of a threat, or be part of a natural process; in any case, consultation with a gynecologist is necessary;
• fainting and dizziness indicate sudden surges in sugar, so the entire daily diet should be divided into small portions, increasing the number of doses;
• emotionally, there is instability, fears, doubts, and worries about the assigned responsibility appear.

Child

The baby reaches a size of 1.7-2 cm, with a large head and small body resembling a tadpole. This is a very important period, as the formation of the spinal cord and brain occurs. The small heart beats and the blood circulates. At this time, it is important for the mother to continue taking folic acid for the normal development of the nervous system and to ensure adequate sleep and rest.

6th week of pregnancy

This week you can use ultrasound to measure the CTE (coccygeal-parietal size), its norm of 5-6 mm indicates correct development. In addition, in the photographs you will be able to see the tubercles of the arms and legs, the formation of fingers is beginning, and soon they will become full-fledged limbs. In the meantime, the formation of the mouth, chin, and cheeks is underway.

Changes in the expectant mother:

• hormonal changes begin to affect eating habits, you constantly feel hungry, or vice versa, foods cause nausea;
• weight gain is not yet happening, if there is toxicosis, the woman may even lose weight;
• if the discharge changes, is accompanied by a specific odor and discomfort, you need to urgently consult a doctor, the risk of fungal diseases is high;
• The area in the lower abdomen may increase, which is easy to detect by clothing; the lack of muscle tone of the uterus gives this effect.

Avoid any contact with chemicals, detergents, tobacco smoke. You should also not visit bathhouses, beaches, solariums, and swimming pools.

7 weeks pregnant

The main feature is the replacement of the corpus luteum with the placenta, which by this time should be fully formed and perform its nutritional and protective functions. The risk is present if previous infections have led to abnormalities.

Fetal development by week of pregnancy description with photo:

• grows by leaps and bounds, reaching a size of 1.8 cm and a weight of 2 grams;
• Both hemispheres of the brain have already been formed, the construction of the nervous system continues;
• the body is exactly the same size as the head, there is also a small tail on the tailbone;
• blood circulation is completely improved, the placenta now supplies oxygen, nutrients, and protects against toxins, infections, and pathogenic microflora;
• the musculoskeletal system continues to form, fingers are visible, skeletal tissue turns into bone tissue, the embryo can bend its elbows and knees;
• the heart already consists of 4 chambers, pumps blood throughout the small body;
• a nose appears on the face, with nostrils, as well as an upper lip, the auditory system is formed, the rudiments of teeth are formed in the mouth;
• the integument already consists of 2 layers, the top one is the epidermis;
• by the end of the seventh week, a mound appears between the limbs; a little later it will be possible to determine whether it is a boy or a girl.

The expectant mother is already beginning to feel all the difficulties of pregnancy. Toxicosis, nausea and drowsiness may be accompanied by swelling, frequent urination, gas formation and disturbances in the digestive system. The baby develops very quickly, and the uterus reaches the size of an orange, which is accompanied by heaviness and pressure in the lower abdomen. The areolas of the nipples darken, and a line is drawn along the lower abdomen to the navel.

8 weeks pregnant

The main symptoms clearly appear, by which inattentive women, forgetting about the delay, can accurately guess their situation.

Main features:

• the woman’s silhouette is noticeably rounded in the area of ​​the abdomen, chest, hips, the gait becomes smooth and measured;
• the condition of the skin will change, for the better or worse depending on individual characteristics, or rashes and redness will appear, or vice versa - the face will be clean, fresh, without a single spot;
• taste preferences are quite original, the desire to eat something out of season arises very often, or a pregnant woman becomes selective in food, stopping at just a few products.

The baby continues to grow, reaching about 2 cm and weighing 2-3 grams. Almost all systems have been laid out, and their further development continues. The tail disappears, the ability to move his arms and legs chaotically appears, he unclenches his fingers. Bones and joints become stronger every day.

The visual system is formed, the embryo becomes less like an alien, the eyes are located closer to each other. On an ultrasound, you can see the ear canal; the face has a clearer contour with barely noticeable facial expressions. At this time, the baby can already respond to touch.

Week 9

This period is characterized by intensive growth and the transition from embryo to fetus. The head is still quite large and lies on the chest, the arms and legs are well formed. The baby can move through the amniotic fluid as long as its small size (about the size of a grape) allows it. The genital organs are indicated, but it cannot be determined by ultrasound yet; you need to take a blood test.

It is important for a woman to still monitor her health; if bloody, yellow, or green discharge appears, she should consult a doctor. You should also be alert for pain in the lumbar region and lower abdomen. The doctor may recommend a consultation with a geneticist; if necessary, a chorionic villus biopsy is taken to identify developmental anomalies.

Fresh and high-quality products should prevail in the diet. If you suffer from heartburn, you should avoid hot spicy foods. Rosehip decoctions and green tea without sugar will ease toxicosis.

10 week

A calmer period begins, the expectant mother gets used to the new state, and the baby’s systems and organs are already formed, and the development of the brain continues. His weight is approaching 7 grams, his head gradually begins to rise from his chest. The most amazing thing at this time is the development of the brain. The process occurs at incredible speed, with new chains of neurons being formed every minute. The fingers continue to lengthen, but the membranes between them remain. The main organs - liver, kidneys, lungs, intestines - are positioned correctly and continue to improve. The synthesis of sex hormones begins, in girls - estrogen, in boys - testosterone.

The woman’s breasts become even larger and veins appear noticeably. The tummy is round enough to think about comfortable clothes. The uterus continues to grow along with the baby, so the pressure on the pelvic organs increases. It is important to maintain a positive attitude, treat yourself with gifts, and not worry about changing body shapes. It’s worth choosing beautiful underwear and clothes to continue to feel beautiful and happy.

11 week

The baby already weighs about 11 grams, and the size is about 5-6 cm; from the first ultrasound, you can determine the development of the fetus and its compliance with the norms. The heart beats very quickly - 140 beats per minute. The growth of blood vessels in the placenta is activated, the baby grows rapidly and requires more nutrients. The auricles are formed and hair follicles are formed.

For expectant mothers suffering from toxicosis, gradual relief occurs. By 14 weeks, morning discomfort should subside. Increased urination is a normal reaction of the body to hormonal changes. You need to drink clean water, as well as healthy drinks; it is better to limit products containing caffeine. You can also start (if there are no threats) to engage in fitness for pregnant women, and use oils for stretch marks; almond, sesame, and olive are considered the most effective.

12 week

The end of the 3rd month makes you forget about the risks that existed from the day the embryo was conceived. This is the time when a woman is already accustomed to the new state and can enjoy it. There are noticeable changes in appearance. The skin is fresher, more elastic, hair grows better, it has become thicker and silkier. Many pregnant women forget about a balanced diet, believing that during this period they can afford everything.

• You should forget about unhealthy fast foods, snacks, street food; hot, spicy, fatty foods can lead to constipation and affect the baby’s condition;
• do not overeat, trying to fulfill the norm for two; excess weight complicates the process of childbirth and subsequent rehabilitation;
• you need to forget about your own taste preferences when eating cottage cheese, fish, lean meats, nuts, fruits, and vegetables.

The fruit reaches 5 cm and weighs about 12-14 grams. The lungs are gradually strengthened, and the functioning of the gastrointestinal tract is improved. The baby is trying to raise his head and can already suck his finger. Sensitivity to pain appears and reacts to sounds.

Week 13

The 2nd trimester begins, the same recommendations for nutrition and moderate physical activity remain. A woman may notice a completely blurred waistline, and her breasts have increased by several sizes. You need to choose special underwear; discharge from the nipples is often observed - this is colostrum. You can forget about frequent trips to the toilet; raising the uterus relieves discomfort. If you experience nagging pain in the lower abdomen and lower back, you should consult a gynecologist. Discharge normally remains white, transparent, without any pungent odors.

The child weighs from 15-20 grams, his height reaches 6-7 cm. The baby's sensitivity is rapidly developing. It can react to temperature changes, light, music, noise, pain.

Physiological development:

• the eyes move closer and closer to each other;
• bones continue to harden, and muscles grow and improve;
• the ears take on their final shape;
• a dream appears, it lasts only a few minutes;
• motor activity includes various movements; in addition to bending, it can cross limbs and make chaotic swings.

Week 14

The expectant mother gradually passes all her fears and doubts. She learns to enjoy the harmony of life, and her priorities are reassessed. The uterus continues to rise and the breasts continue to grow. A woman already needs to choose looser and more comfortable clothes. At this time, you should not indulge yourself in sweets; it is better to provide your child with high-quality protein. The average weight gain rate is 1.5-2 kg from conception, it is important to watch the clock and not overeat.

The baby continues to develop rapidly, reaching a weight of 50 grams, with a height of 10 cm. Pronounced facial expressions appear, as well as sleep and wakefulness patterns. The respiratory system is trained, insulin production begins. Heart rate often depends on the behavior of the mother. Her bad habits and stress can lead to a noticeable increase in the fetal heart rate.

If you haven’t had an ultrasound yet, now is the time. The doctor can accurately measure the child’s parameters and determine compliance with standards.

Week 15

The expectant mother continues to lead an active lifestyle, not forgetting to monitor her health.

Discomfort may be associated with:

• with the condition of your teeth, you definitely need to see a dentist to cure caries and bleeding gums in order to prevent infection;
• reduced immunity leads to respiratory diseases, it is important to limit trips to public places; if symptoms appear, the doctor will advise safe medications;
• weakness, the desire to rest, to get enough sleep - this is typical for such hormonal changes, you should not deny yourself, because when the baby is born, sleep will become a luxury;
• if the veins become enlarged, you need to choose the right shoes; you may need light exercises to relieve fatigue;
• pain in the lower abdomen is not always associated with abnormalities; the growth of the uterus is reflected in the stretching of muscles and ligaments.

The baby reaches the size of an apple, his movements are still active, and his sleep is short. The eyes are still closed, but the optic nerves are formed, the child can distinguish between light and shadow. The first hairs are emerging, the sweat glands are working.

Week 16

The fetus becomes more and more like a baby. His body is covered with light fluff, the skin is still thin, and blood vessels are visible. Height is 11-14 cm, and weight reaches 110 g. The chemical composition of the blood changes, red blood cells, platelets, lymphocytes appear, and hemoglobin is synthesized. All features are already clearly expressed on the face, eyebrows and eyelashes emerge. The fetus is covered with a special white lubricant that protects the thin skin until the birth process.

The expectant mother continues to monitor her diet; sudden changes in weight will lead to dangerous changes in blood pressure. The gait becomes like that of a duck, and fatigue appears in the legs. If this is not your first pregnancy, you may already feel fetal movements.

Week 17

A woman's performance decreases. She needs the support of loved ones more than ever. Heaviness, pain in the sacrum, weight gain, affect the mother’s activity and her rapid fatigue. From time to time it can feel hot or cold, sudden changes in mood are characteristic of accumulated fatigue. The support of not only the husband, but also all relatives is important; someone can cook soup, someone can take documents to the hospital.

The baby reaches a height of 13 cm, sleeps most of the time, and then stretches and grimaces. Reacts well to sounds, sharp, loud ones are scary, but mom’s voice will calm him down. The pituitary gland and adrenal glands are actively working, and in girls the formation of internal reproductive organs begins.

Week 18

The tummy is quite pronounced and the mother has to choose sleeping positions; the left side is considered the most favorable for childbirth. A good appetite must be restrained; during this period, significant weight gain is observed. Carbonated drinks and large portion sizes can lead to constipation and bloating. A high need for calcium can affect the condition of teeth, so the diet must include fermented milk products. Breast sensitivity, darkening and expansion of the areola, increase in size, provoke depression. Don’t despair; after giving birth, if you follow a balanced diet, you will be able to quickly return to normal.

The child reaches 18 cm and weighs 200 g. It is important to talk to your baby, this stimulates the development of his central nervous system. Mom can feel the first tremors during the period of activity; the musculoskeletal system develops. Unique fingerprints have already appeared on the fingers.

Week 19

Toxicosis and heartburn have finally subsided, but a pregnant woman may be bothered by itching of the skin of her growing abdomen. It is worth using special creams or oils to reduce sensitivity. For fatigue and leg cramps, Magnesia preparations may be prescribed. Relaxing exercises will help you cope with back pain. It is important to alternate between activity and rest modes. If there are no threats or pathologies, you need to walk a lot and do feasible work. Self-prescribed bed rest can complicate the birth process due to muscle weakness.

The child reaches 220-250 g, sleeps most of the day, and while awake you can feel his movements. If the mother walks, the baby is rocked, but as soon as she lies down to rest, tremors are immediately felt. The sebaceous glands continue to produce white protective lubricant.

At this time, it is necessary to undergo a control urine test and a scheduled second ultrasound. On it you can already find out the gender and get a photo of the baby.

Week 20

A period of rest for the expectant mother, she enjoys her condition and blooming appearance. The tummy is small, neat, and does not interfere with movement and doing usual things. By her feelings, a woman can understand how the baby is developing. Strong intense tremors will signal a lack of oxygen; you need to go out into fresh air or ventilate the room. If this happens after physical activity, you need to lie down to rest, then the baby will calm down. It is recommended that a woman sleep on her side to avoid squeezing the veins. The basis of nutrition remains foods rich in calcium and iron - beef, buckwheat, cottage cheese, spinach, prunes.

The baby weighs about 280 grams, his height is 22-25 cm, he can not only yawn and tumble, but also play. The legs become longer and more proportional to the body, the head gradually becomes smaller. The skin thickens and already consists of 4 layers, protective lubricant continues to be produced. Nails appear on the arms and legs, and the first hairs appear on the head.

21 weeks

The most interesting thing at this stage is the opportunity for the mother to shape the child’s future taste preferences. If you eat hot, spicy, salty, sweet dishes, you will have to make a lot of effort to get your baby to try broccoli, buckwheat or carrots.

For the mother, problems remain with flatulence, strain on the veins and appetite control. Extra pounds can lead to a large fetus and complications during childbirth. Small portions and frequent meals will save you from feeling hungry. Nails and hair have significantly accelerated their growth, and their condition has also changed for the better.

The child reaches a height of 26 cm, weight – 330-350 g. Outwardly, he already looks like a newborn, all that remains is to gain kilograms and grow. Amniotic fluid allows the baby to know what mom ate for lunch. When the fetus moves, noticeable bumps may appear on the abdomen.

Week 22

At this time, the belly is already noticeable, even under outer clothing; if there are no medical prescriptions, the woman can continue to lead a normal life. The condition of the skin improves, the expectant mother blossoms. It is worth paying attention to swelling; if there is fluid retention, you need to reduce the amount of salt. If physiological anemia is detected, additional tests are performed to make an accurate diagnosis. You already need to undergo a routine ultrasound to determine the development of the fetus, as well as the condition of the placenta.

The child weighs about 410 grams, height - 28-30 cm. Large sizes make physical activity difficult; most of the time he is in a curled up position. The formation of the brain slows down, it is the turn of the nervous system to improve, and neurons are fully formed.

Week 23

You can still enjoy your rest period. Heartburn and toxicosis are a thing of the past, now the main thing is not to gain excess weight. On average, a woman gains 5-7 kg by this time. The belly rises higher, the expectant mother may feel tension and fatigue in the lower parts of the spine. If this period falls on a hot summer, swelling is difficult to avoid. It is worth slightly reducing the amount of liquid, and also avoiding salty foods; it is useful to put your feet on elevated surfaces - pillows - while resting. If cramps occur, you need to avoid walking shoes, and also enrich your diet with foods containing calcium and vitamin E.

Child development:

• the weight has increased to 400-420 g, but the fruit itself looks wrinkled, soon it will accumulate subcutaneous fat and all wrinkles will disappear;
• the main processes that the baby is engaged in are the absorption of nutrients in the liquid, and then excretion in the urine, due to the frequent change of amniotic fluid, this is not dangerous for the child;
• the preparation of the respiratory organs begins, they are not yet fully formed, but the child is already doing the first test exercises;
• He sleeps most of the day, he develops the REM sleep phase, which means he is able to dream.

Week 24

The baby grows along with the belly, this can lead to the appearance of stretch marks. They can upset women, especially bright red or brown ones. But after childbirth, with proper physical activity, you can return to your previous shape.

Expectant mothers feel great - the first dangerous trimester has passed, but childbirth is still far away. You can work, relax, chat with friends, go on picnics. Recommendations remain on nutrition, as well as the correct distribution of time - active mode and sleep.

• if the doctor places the fetus in breech position, do not be upset; before birth, he will change his position;
• the baby has grown to 25 cm and weighs about 500 grams;
• inhales and exhales, but oxygen continues to flow through the umbilical cord;
• further formation of the brain occurs, an increase in neural connections;
• The baby can already play with the umbilical cord, grimace, frown, and suck his finger.

If you experience spotting blood, acute pain in the lower abdomen and lower back, you should urgently consult a doctor; hospitalization may be required to maintain it.

Week 25

Every woman's belly will look different, even though everyone's uterus becomes the size of a ball. There is pressure on the stomach, which often causes heartburn. To avoid digestive problems, in particular constipation, it is recommended to include vegetables and cereals in the diet. If there is a low level of hemoglobin in the blood, therapy with iron-containing drugs is prescribed. To reduce the load on your back, you can already start wearing a bandage.

Baby development:

• in case of premature birth, the newborn will be viable, he will be placed in special conditions for maturity equal to 40 weeks;
• weight becomes 700 g, height 30-35 cm;
• The skeletal system is strengthened, muscles are improved, a grasping reflex appears, the baby clenches his hands into fists and determines whether his leading hand is right or left.

Week 26

The load on the female body increases every day. Forgetfulness and absent-mindedness are possible, so it’s time to think about maternity leave. Walking becomes more and more difficult, especially if you have gained excess weight, normal fluctuations are from 6-8 kg. When moving, tension may be felt in the lower back, and the gait approaches a pendulum gait. If there is uterine tone, it is important to monitor your condition and prefer bed rest. If contractions or bleeding occur, medical attention is urgently required.

• the fetus already weighs about 1 kg, and its height is 33-35 cm;
• pigmentation changes due to the accumulation of subcutaneous fat, the skin brightens;
• the muscles become stronger; if the baby accidentally pushes the internal organs, the mother may feel painful discomfort.

To fill your life with exclusively pleasant emotions, do not forget about nutrition and exercise for pregnant women.

Week 27

It becomes more and more difficult for mom to do her usual things. Fatigue sets in quickly and you have to rest more. This is a natural process that allows a woman to take a short vacation. It is advisable to devote this period to your favorite activities and hobbies, because after the birth of the baby there will be no time for it. At week 27, you can begin to rapidly gain weight; it is important to control this process with the frequency and number of servings. Shortness of breath and heartburn appear, which is associated with enlargement and pressure of the uterus. Breasts become increasingly larger and change by 1-3 sizes during pregnancy.

Child development:

• the brain grows and improves, the foundations of cognitive thinking are laid - memory, attention, and the main traits of temperament are also determined;
• the need for calcium does not decrease, the final formation of bone tissue has not yet been completed;
• there is further accumulation of subcutaneous fat and changes in skin pigmentation;
• the placenta helps form the first immunity, which will protect the newborn for the first 6 months.

Week 28

For most mothers, maternity leave has already begun. Depending on the kilograms gained, the pregnant woman’s feelings also change. More than 9 make movements clumsy, provoke fatigue, drowsiness, and digestive problems.

It is worth listening to the doctor’s recommendations and organizing fasting days. By this time, the baby has already taken the correct position, the mother can even count the number of kicks; normally, about 10 should occur in 2 hours. Back pain will be relieved by a bandage and special gymnastics, which will also be useful during childbirth.

Child Formation:

• accumulation of subcutaneous fat continues, wrinkles are smoothed out, the skin gradually brightens;
• convolutions form in the brain, further growth and improvement of the rudiments of intelligence continues;
• emotions appear; the baby may frown or react to any discomfort with movements of his limbs.

If there is a Rh conflict, immunoglobulin therapy may be required; this will not harm the child, but will only avoid the risk of oxygen starvation of the fetus.

Week 29

The baby is already feeling cramped and it seems to the mother that the baby has become stronger. In fact, his weight reaches 1.5 kg, his height is 36-40 cm. The optic nerves allow him to examine light more clearly and blink when its intensity changes. The child coughs and hiccups, and the mother feels it. The emotional sphere also does not stand still - the ability to cry appears. The internal organs are already formed. The muscles continue to grow, the respiratory system improves.

Woman's feelings:

• if the expectant mother has not yet changed her wardrobe, it’s time to do this, don’t be upset about loose, loose-fitting styles, in a few months you’ll be able to get back into shape;
• the condition of the skin changes, it becomes drier, pigmentation appears;
• in order to learn how to control your body during childbirth, it is advisable to master Kegel exercises; if there are no contraindications, yoga classes are useful;
• irritation and fatigue increase, the stomach becomes larger, the load when walking increases, sleep only on the side.

Week 30

The growth of the abdomen also stretches the skin, it becomes thinner. Stretch marks also appear in the hip area. Constipation and swelling can be corrected with proper nutrition. If the mother experiences dizziness and weakness, it is worth increasing the rest time. It is important to learn relaxation techniques during this period; they will help cope with insomnia and accumulated fatigue.

Child development:

• the process of interaction with his mother is improving, he calms down when his belly is stroked, he reacts violently in an uncomfortable environment - a stuffy room, tobacco smoke;
• small hairs - lanugo - that covered the baby's body gradually disappear, but in some cases, the newborn may appear with it;
• The brain continues to grow rapidly, the number of convolutions and grooves increases.

31 weeks

At this time, all previous discomfort sensations intensify. The uterus has displaced all the internal organs, so shortness of breath becomes more frequent and breathing becomes difficult. Cramps, swelling, and back pain interfere not only during the day, but also at night, causing insomnia. A positive attitude, a relaxing massage, and yoga classes will help you cope. It is worth reducing the amount of fluid, urination occurs very often, and the woman may even limit her walks. Such sacrifices are not necessary, you need to stick to the right diet and not drink an hour before going out.

Child development:

• height reached 35-43cm, weight – up to 1.6 kg;
• trains control of the basic 5 senses;
• neural connections grow at feverish speed;
• The period of wakefulness increases, the baby is busy with his own business - breathing, looking, blinking, sucking a finger, clenching his fists, pushing.

Week 32

The body is gradually preparing for the process of childbirth. Some may even feel training contractions. The stomach is already big, it can pull, it’s worth wearing a bandage. The woman’s movements and gait have become clumsy, she is slower in performing usual tasks. You shouldn’t deny yourself the desire to sleep or buy new clothes, and you’ll have to forget about sweets and spicy dishes. It takes longer to choose a comfortable position, the tremors become more intense.

Child development:

• height up to 46 cm, weight 1.6-1.8 kg;
• the fetus is still in a breech position, but may already turn head down;
• Brain development improves if you talk to your baby, read books, listen to music;
• The muscular system continues to strengthen, movements are better coordinated.

It's time to undergo the 3rd planned ultrasound, you can find out not only the size and formation of the fetus, but also clearly see it on the screen. Information about the state of amniotic fluid, the uterus, and the maturity of the placenta will also become important.

Week 33

On average, a woman gained 10-12 kg during pregnancy. Hormonal levels increase, which can cause bleeding gums. Excessive irritability is caused by fear of the upcoming birth. It is important to maintain a positive attitude, fill life with joyful emotions, and communicate with pleasant people. It is worth remembering about feasible physical activity, it is necessary for muscle tone, otherwise it will be difficult to control your body during childbirth.

• height - 40-46 cm, weight -2100-2300;
• the child should already be in the desired position; if not, during childbirth this will require additional attention from the obstetrician;
• the sucking reflex necessary for breastfeeding is improved;
• The musculoskeletal system continues to develop, so cottage cheese is required throughout the gestation period;
• The fetus already looks like a newborn; cheeks and folds appear on the arms and legs.

34 week

Hormonal changes allow the mother to be in a good mood. She's tired of the discomfort and can't wait for the baby to appear. The weight increases noticeably to 12-15 kg, and the breasts continue to grow. The line from the navel to the lower abdomen, as well as the areola of the nipples, darkens. The nesting instinct is at its peak, the expectant mother is busy with household chores.

Baby development:

• height 41-47 cm, weight 2100-2400;
• the skin of the fetus is light and smooth, it is covered with a protective lubricant that facilitates the passage of the birth canal;
• When born at this stage, the child can breathe on his own and does not require intensive rehabilitation therapy.

Week 35

The most crucial moment begins, preparation for childbirth. It is useful for the expectant mother to take special courses in consultation. Choosing a partner for childbirth does not have to be your husband; a close person - a friend, mother - can support and reassure you. The bag for the maternity hospital should already be packed so that the woman does not get nervous about little things. The abdomen reaches its maximum size, fatigue sets in quickly when walking, and swelling appears. It is important not to overeat at this time, otherwise the baby will be large and the birth process will be more complicated.

Child development:

• training of the respiratory system, sucking and swallowing reflex continues;
• the amount of amniotic fluid decreases, which causes discomfort for the baby, the body reports that it is time to change living conditions;
• the endocrine, nervous and immune systems continue to improve;
• gradually the baby lowers, the mother can feel this in easier breathing and reduced pressure on the back.

36-40 weeks

Everything is ready for the long-awaited emergence of a new life. 2 weeks before giving birth, the stomach drops and becomes stiff - this is a signal that the uterus is becoming toned. Contractions, both training and real, can begin at any moment. The woman has already gained from 9 to 16 kg, immediately before giving birth, a slight decrease is observed. It is mandatory to attend a consultation once a week; the doctor monitors the condition of the fetus and heartbeat.

Signs of the onset of labor:

• appetite increases;
• discomfort occurs in the lower abdomen, after which it will turn into pain;
• contractions begin in spasms with a frequency of 5 times per hour;
• the body begins to cleanse itself - vomiting and diarrhea are possible;
• the release of the mucus plug and the discharge of amniotic fluid is a direct signal of the onset of labor; immediate hospitalization is required.

The child reaches a size of 50-54 cm and weighs about 3-3.5 kg. He becomes very cramped in the mother's womb; all organs are formed and ready to support life after birth. The baby is sensitive to light, can distinguish colors, and very soon he will meet his mother. The female body also prepares - the joints become softer and more elastic. If necessary, you will need to undergo an ultrasound to determine the condition of the placenta and the location of the fetus. The child does not stop developing even after birth, the process continues only now he can feel the warmth of his mother’s hands.

The development of the human embryo is one of the most interesting phenomena in biology and medicine. From just two cells, within 9 months, a new life arises - the child that the parents had been waiting for and wishing for. How does the development of the embryo and fetus occur?

Stages of embryo development

Strictly speaking, an embryo is a human embryo from fertilization to the 10th obstetric week. From the 10th week, the embryo is considered a fetus, and the further period is called fetal (from the Latin fetus - fruit). Before this period, the development of the embryo by day (from the moment of fertilization) takes 49 days.

The first trimester of pregnancy is the most difficult and critical. During this period, all harmful influences can lead to disruptions in the development process and the formation of organs and systems of the unborn baby. Let's find out what stages of embryo development have been identified by scientists.

Stages of embryo development

Immediately after fertilization of the egg, the genetic material of the mother and father merge, forming a new, completely unique set of genes. In addition, the synthesis of substances necessary for further growth is launched.

Approximately 30 hours after fertilization, the first division occurs. 2 cells are formed, then 4, 8, 16 and so on. The embryo does not increase in size much as the number of cells increases. When a certain number of cells is reached, the rate of division slows down. At this point the embryo is called a morula.

Morula cells begin to migrate to the periphery, resulting in the formation of a cavity in the center of the embryo. This stage of development is called blastula. At this stage of development, it is possible for the blastula to separate to form identical twins. The blastula contains several hundred cells.

In the future, the skin, nervous system, and eyes are formed from the ectoderm.

From the mesoderm - bones, muscles, blood vessels, kidneys.

From the endoderm - the gastrointestinal tract, respiratory system.

At this stage the embryo is called a gastrula. This happens 8-9 days after fertilization. Around this time, implantation occurs - the implantation of the embryo into the uterine mucosa.

Embryo development (photo by Lennart Nilsson). Embryo on the lining of the uterus:

Embryo with heart bud:

The next stage, called neurula, begins the formation of the nervous system. During this period, failures are possible that will lead to severe pathology of the fetus. The reason is most often banal - a cold, medication or lack of vitamins and minerals. This is why it is important to eat right in the first months of pregnancy and avoid stress and colds.

Organogenesis - laying down of organs

Further development of the embryo occurs with the formation of vital organs. On day 20, the rudiment of blood vessels and the baby’s heart is formed. It will make its first contraction between 22 and 28 days after fertilization and will not stop until the very end of life. During the same period, the lungs, ears, mouth, and spinal cord are formed. The spleen appears. By the way, during this period we all had tails.

By the end of the first month, the embryo has the rudiments of eyes, small arms and legs. The buds are being laid.

One and a half months after fertilization, the fetal heartbeat can be heard during an ultrasound. The embryo begins to make spontaneous movements. During this period, almost all vital organs are already formed.

With the beginning of the second trimester, unpleasant phenomena for the mother, in the form of attacks of nausea, heightened perception of smells, and the frequent need to visit the restroom, cease. However, you should pay a visit to the doctor, do the necessary tests and, of course, an ultrasound to determine the sex of the child.

Further development of the fetus occurs with weight and height gain. Before giving birth, the baby should recover up to 3 kg and grow to about 50 cm. While doing this, he will suck his finger, cry silently, kick and shove quite noticeably, and sleep.

Despite the fact that all organs are already in place, their activity is low. The lungs are folded like a parachute. They will have to open up with the first breath. The liver and kidneys are still idle. Their function is almost entirely performed by the mother's body.

Only the baby’s heart works at 200%. The normal heart rate for babies in the womb is between 120 and 160 beats per minute. At the same time, “cosmetic” changes occur. Marigolds, eyelashes, eyebrows, and fluff appear on the skin. The baby is preparing for birth.

How is the gestational age calculated?

The development of the embryo by week, from the date of the last menstruation to birth, is counted in obstetric weeks. From the actual period of pregnancy, from the moment of fertilization, the obstetric period differs by 2-3 weeks, since on average 14 days pass from the moment of the last menstruation to the moment of fertilization. Therefore, a normal pregnancy of 40 obstetric weeks is equal to 38 weeks from the moment of fertilization.

The birth of a child is a real miracle. But miracles must be treated very carefully. Be sure to visit your doctor regularly and get the necessary tests. Protect yourself from colds and dress according to the season. Do not engage in active sports. Smile more often. After all, you will soon be a mother.

The development of the human body begins from the very first day of fertilization of an egg by a sperm. The stages of embryogenesis are counted from the moment the cell begins to develop, which subsequently forms an embryo, and from it a full-fledged embryo appears.

The development of the embryo fully begins only from the second week after fertilization, and starting from the 10th week, the fetal period is already underway in the mother’s body.

First stage of zygote

Absolutely all somatic cells of the human body have a double set of chromosomes, and only sex gametes contain a single set. This leads to the fact that after fertilization and the fusion of male and female germ cells, the set of chromosomes is restored and becomes double again. The resulting cell is called a “zygote”.

The characteristics of embryogenesis are such that the development of the zygote is also divided into several stages. Initially, the newly formed cell begins to divide into new cells of different sizes, called morulae. The intercellular fluid is also distributed unequally. A feature of this stage of embryogenesis is that the morulae formed as a result of division do not grow in size, but only increase in number.

Second phase

When cell division ends, a blastula is formed. It is a single-layer embryo the size of an egg. The blastula already carries all the necessary DNA information and contains cells of unequal size. This happens already on the 7th day after fertilization.

After this, the single-layer embryo goes through the gastrulation stage, which is the movement of existing cells into several germ layers - layers. First, 2 of them are formed, and then a third appears between them. During this period, the blastula forms a new cavity called the primary mouth. The previously existing cavity completely disappears. Gastrulation allows the future embryo to clearly distribute cells for the further formation of all organs and systems.

From the first formed outer layer, all skin, connective tissues and the nervous system are formed in the future. The lower layer, formed by the second, becomes the basis for the formation of the respiratory organs and excretory system. The last, middle cellular layer is the basis for the skeleton, circulatory system, muscles and other internal organs.

The layers in the scientific community are called accordingly:

• ectoderm;
• endoderm;
• mesoderm.

Third stage

After all of the above stages of embryogenesis have been completed, the embryo begins to grow in size. In a short time, it begins to look like a cylindrical organism with a clear distribution into the head and tail ends. The growth of the finished embryo continues until the 20th day after fertilization. At this time, the plate previously formed from cells, the predecessor of the nervous system, is transformed into a tube, which later represents the spinal cord. Other nerve endings gradually grow from it, filling the entire embryo. Initially, the processes are divided into dorsal and abdominal. Also at this time, the cells are distributed for further division between muscle tissue, skin and internal organs, which are formed from all cell layers.

Extraembryonic development

All initial stages of embryogenesis occur in parallel with the development of extraembryonic parts, which will subsequently provide nutrition to the embryo and fetus and support vital functions.

When the embryo has already fully formed and exited the tubes, the embryo is attached to the uterus. This process is very important, since the future functioning of the fetus depends on the correct development of the placenta. It is at this stage that embryo transfer occurs during IVF.

The process begins with the formation of a nodule around the embryo, which is a double layer of cells:

• embryoplast;
• trophoblast.

The latter is the outer shell, therefore it is responsible for the effectiveness of attachment of the embryo to the walls of the uterus. With its help, the embryo penetrates the mucous membranes of the female organ, implanting directly into their thickness. Only reliable attachment of the embryo to the uterus gives rise to the next stage of development - the formation of a child's place. The development of the placenta occurs in parallel with its separation from the litter. The process is ensured by the presence of a trunk fold, which, as it were, pushes the walls away from the body of the embryo. At this stage of embryo development, the only connection with the placenta is the umbilical peduncle, which subsequently forms a cord and provides nutrition to the baby for the rest of the intrauterine period of his life.

Interestingly, the early stages of embryogenesis in the area of ​​the umbilical stalk also have a vitelline duct and a yolk sac. In non-placental animals, birds and reptiles, this sac is the yolk of the egg, through which the embryo receives nutrients during its formation. In humans, although this organ is formed, it has no influence on the further embryonic development of the body, and over time it is simply reduced.

The umbilical cord contains blood vessels that carry blood from the embryo to the placenta and back. Thus, the embryo receives nutrients from the mother and removes metabolic products. This part of the connection is formed from the allantois or part of the urinary sac.

The embryo developing inside the placenta is protected by two membranes. In the internal cavity there is a protein liquid, which is an aqueous shell. The baby swims in it until it is born. This sac is called amnion, and its filling is called amniotic fluid. All are enclosed in another shell - the chorion. It has a villous surface and provides the embryo with breathing and protection.

Step-by-step review

In order to analyze human embryogenesis in more detail in a language understandable to most, it is necessary to start with its definition.

So, this phenomenon represents the intrauterine development of the fetus from the day of its fertilization until birth. This process begins only after 1 week after fertilization, when the cells have already finished dividing and the finished embryo moves into the uterine cavity. It is at this time that the first critical period begins, since its implantation should be as comfortable as possible for both the mother’s body and the embryo itself.

This process is carried out in 2 stages:

• tight attachment;
• penetration into the thickness of the uterus.

The embryo can attach to any part of the uterus except the lower part. It is important to understand that this entire process takes at least 40 hours, since only gradual actions can ensure complete safety and comfort for both organisms. After attachment, the attachment site of the embryo gradually fills with blood and becomes overgrown, after which the most important period of development of the future person begins - embryonic.

First organs

The embryo attached to the uterus already has organs that somewhat resemble a head and tail. The very first protective organ to develop after successful attachment of the embryo is the chorion. To more accurately imagine what it is, we can draw an analogy with the thin protective film of a chicken egg, which is located directly under the shell and separates it from the protein.

After this process, organs are formed that provide further nutrition to the crumbs. Already after the second week of pregnancy, the appearance of an allantois, or umbilical cord, can be observed.

Third week

The transfer of embryos to the fetal stage is carried out only upon completion of its formation, but already in the third week one can notice the appearance of clear outlines of future limbs. It is during this period that the body of the embryo separates, the torso fold becomes noticeable, the head stands out and, most importantly, the future baby’s own heart begins to beat.

Power change

This period of development is also marked by another important stage. Starting from the third week of life, the embryo stops receiving nutrition according to the old system. The fact is that the reserves of the egg are depleted by this moment, and for further development the embryo needs to receive the substances necessary for further formation from the mother’s blood. At this point, to ensure the efficiency of the entire process, the allantois begins to transform into the umbilical cord and placenta. It is these organs that will provide the fetus with nutrition and release it from waste products throughout the remaining intrauterine time.

Fourth week

At this time, it is already possible to clearly determine the future limbs and even the places of the eye sockets. Externally, the embryo changes slightly, since the main emphasis of development is on the formation of internal organs.

Sixth week of pregnancy

At this time, the expectant mother should pay special attention to her own health, since during this period the thymus gland of her unborn baby is being formed. It is this organ that will be responsible for the functioning of the immune system throughout life. It is very important to understand that the mother’s health will determine the ability of her child to withstand external stimuli throughout his independent life. You should not only pay attention to the prevention of infections, but also protect yourself from nervous situations, monitor your emotional state and the environment.

Eighth seven-day period

Only from this time threshold can the expectant mother find out the gender of her child. Exclusively at the 8th week, the sexual characteristics of the fetus and the production of hormones begin to develop. Of course, you can find out the gender if the child himself wants it and turns to the right side during an ultrasound.

The final stage

Starting from the 9th week, fertilization ends and begins. By this point, a healthy baby should already have all its organs formed - they just have to grow. At this time, the child’s body weight is actively gaining, his muscle tone increases, and the hematopoietic organs are actively developing; the fetus begins to move chaotically. Interestingly, the cerebellum is usually not yet formed at this point, so coordination of fetal movements occurs over time.

Dangers during development

Different stages of embryogenesis have their own weaknesses. To understand this, you need to consider them in more detail. Thus, in some periods of human embryogenesis, it is sensitive to infectious diseases of the mother, and in others, to chemical or radiation waves from the external environment. If problems arise during such a critical period, the risk of the fetus developing birth defects will increase.

To avoid this phenomenon, you should know all stages of embryo development and the dangers of each of them. Thus, the period of blastula is particularly sensitive to all external and internal stimuli. At this time, most of the fertilized cells die, but since this stage passes through the first 2, most women do not even know about it. The total number of embryos dying at this time is 40%. at the moment it is very dangerous, since there is a risk of rejection of the embryo by the mother’s body. Therefore, during this period you need to take care of yourself as much as possible.

The transfer of embryos into the uterine cavity marks the beginning of the period of greatest vulnerability of the embryo. At this time, the risk of rejection is no longer so great, but from the 20th to the 70th days of pregnancy, all vital organs are formed; with any negative effects on the mother’s body at this time, the likelihood of the unborn baby developing congenital health abnormalities increases.

Usually, by the end of the 70th day, all organs are already formed, but there are also cases of delayed development. In such situations, with the beginning of the fertile period, a danger appears for these organs. Otherwise, the fetus is already fully formed and begins to actively increase in size.

If you want your unborn child to be born without any pathologies, then monitor your health both before and after the moment of conception. Lead the right lifestyle. And then no problems should arise.

There are 4 periods in human embryogenesis:

1. Beginner(1 week of development, until the implantation of the embryo into the uterine mucosa).

2. Embryonic(2-8 weeks).

3. Prenatal(9-12 weeks). =larval in animals

4. Fertile(13th week – birth). =metamorphosis

During the embryonic period, gastrulation, blastulation, and neurulation occur. Intense organogenesis and anatomical formation of organs take place in the prefetal stage. The fetal period is characterized by the creation of a fetus under the protection of the membranes.

In the initial period there is zygote– 1 cell of the embryo, in which individual sections of the cytoplasm are determined, DNA and proteins are synthesized. The zygote has a bisimitric structure. Gradually, the relationship between the nucleus and the cytoplasm is disrupted, resulting in stimulation of the process of division - crushing

The cleavage stage is a period of intense cell division. The size of the embryo does not increase, and synthetic processes are active. Intensive synthesis of DNA, RNA, histone and other proteins occurs.

Crushing performs the following functions:

A sufficient number of cells necessary for the formation of tissues and organs are formed.

Redistribution of yolk and cytoplasm between daughter cells. The 1st and 2nd fission furrows run along the meridian, and the 3rd along the equator. Closer to the animal pole.

The plan of the embryo is determined - the dorsal-ventral axis, the anterior-posterior axis.

Nuclear-cytoplasmic relationships are normalized. The number of nuclei increases, but the volume and mass remain the same.

Gradually, division slows down.

In a woman, one day after fertilization, fragmentation begins in the second third of the oviduct. Simultaneously with this process, the zygote moves along the oviduct to the uterine cavity. Two types of cells are formed: smaller ones, which later give rise to auxiliary tissue - trophoblast, and larger cells - embryoblast - “embryo rudiment”, which will give rise to all the cells of the body and the cells of some auxiliary parts.

On 6-7 day After fertilization, the human embryo measures 0.5 mm and consists of 200 cells. It begins to attach to the inner wall of the uterus, penetrates the uterine mucosa, and implantation occurs. Within 24 hours, it is half immersed, and after another day, it is completely immersed. Then the trophoblast develops powerfully - villi and outgrowths are formed that come into contact with the mother’s blood, receiving nutrients and supplying them to the embryo.

On 2 weeks extraembryonic parts grow, i.e. those parts that are formed by the embryo, but first play an auxiliary role - amnion, chorion, yolk sac. These are provisional organs - coenogenetic structures that do not take part in the formation of an adult organism. The cellular material from which the embryo develops is the embryonic shield. In the early stages, preparatory work is underway; it is not the embryo itself that develops, but parts that create the necessary conditions for the existence of the embryo and provide the functions of respiration, nutrition, excretion of metabolic products, creating a liquid environment around the embryo to protect it.

3 week– the placenta is formed, Greek. "Cake". Consists of 2 parts - embryonic and maternal. Germinal – trophoblast and some other tissues (chorion – Greek “shell, afterbirth”). Maternal - highly modified uterine mucosa. In it, blood vessels are destroyed, connective tissue is loosened, and the epithelium is destroyed. The chorionic villi “bathe” in maternal blood. The area of ​​the placental plexus is 5 square meters, and the total length of the chorionic villi is 5 km. The maternal and embryonic organisms do not have a common blood flow, the blood does not mix. Nutrients pass through the walls of the chorion. In a 3-week-old embryo, umbilical vessels appear, growing into the walls of the chorion and performing functions. Food.

4 week. The dimensions of the embryo together with the chorion are 5-7 mm. A new stage begins. The body of the embryo is separated from the extraembryonic parts. The embryo rises above the amniotic fluid, with which it is then connected only by the umbilical vessels. During embryonic development, a yolk sac appears early in humans - the first hematopoietic organ that stores and processes yolk, the first organ of respiration and nutrition. Primary germ cells begin to form in the yolk sac. There is an intestine that is blindly closed on both sides. The liver is a hematopoietic organ. The heart is beating. By the end of 4 weeks there is a rudiment of the respiratory system. Sizes up to 30mm.

The intestines grow in length, do not fit in the straightened state and begin to bend. By the end of 4 weeks, shoulder blades appear on the sides. Nerves and muscles grow into them - future arms and legs. By the end of the week, there is differentiation into parts; by the 5th week, sections of the embryo protrude on the sides of the back of the head and neck - 4 pairs of gill slits are formed, parts of the foregut protrude from the inside, forming 4 gill pouches. There is no connection between the gill slits and the gill pouches. The middle ear is formed from 1 pair of gill slits. The rest are the thyroid and thymus glands.

From 4 weeks the nervous system begins to form. Formation of the neural tube (neural plate - neural groove - neural tube). At the anterior end of the neural plate, 3 brain vesicles appear; at week 6, there are already 5 brain vesicles that correspond to parts of the brain; auditory vesicles, optic cups, and olfactory pits appear. Mesoderm differentiation occurs. A tail is formed (day 34) up to 10 mm.

At 2 months The primary sex glands are formed, where the primary sex cells migrate from the yolk sac.

On 8 weeks rapid development of the amniotic membrane and accumulation of fluid occurs.

9-10week– kidney formation, nephrons are formed throughout embryogenesis and another 20 days after birth.

week 7– formation of dental plates.

Start 3 months. The fruit is formed. Within a month, the tail disappears (cell death under the influence of lysosomal enzymes), leaving rudimentary vertebrae. The head is ahead of the body in development, then the proportions are restored.

Start of 4 months. Sizes 20-22cm. the muscular system is formed and begins to move.

5 month. The entire body is covered with hair.

The upper limbs grow faster than the lower ones and appear earlier.

The development of an embryo week by week is a lifelong journey. Only 300 days separate a tiny egg from becoming a newborn baby, a full-fledged person in whom all organs and systems are formed. Every mother wants to know more about what is happening in her tummy now, but the development process there does not stop day or night. No subsequent stage of development is as stormy and rich in transformations as the perinatal stage. Today we want to take a closer look at the development of the embryo week by week, so that you can have a good idea of ​​the complex path your baby goes through even before birth.

The beginning of the way

Often the expectant mother at this stage does not yet know that she is pregnant, but amazing events are already happening inside her. Pregnancy begins with fertilization, when the egg fuses with the sperm. Only a few hours will pass, and the cell will already begin to divide and descend into the uterus in order to be implanted there and remain for the next 9 months. We will begin to consider the process of embryo development week by week a little later, but for now the egg has approximately 5 days for its journey to the uterine cavity. After seven days, it is no longer a cell, but a multicellular organism that is implanted into the endometrium of the uterus, and the first transformations begin.

The embryo is in its 2nd week of development, now it is securely attached to the wall of the uterus, due to which its nutrition and development will occur in the next 9 months. The most important event of this week is the formation of the neural tube. This is the rudiment of the brain and spinal cord.

We continue to look at the development of the embryo week by week. The third week begins. It is at this time that a wide plate is formed - this is the baby’s brain, and at 21 weeks the tiny heart begins to beat. This brings us to the fourth week, which concludes the first month. Now the baby develops the rudiments of all the main internal organs: lungs and liver, intestines. It is the 4th week of embryo development that is characterized by the formation and development of the spine.

Second month

The first important stage is ending. Most often, a woman already realizes that she is pregnant, but sometimes this is still hidden even from the expectant mother. These are very important days on which the further development of the embryo depends. The first weeks are decisive in many ways, so if you are planning to become parents, you need to monitor your diet and lifestyle. The embryo is still very small, its length is only 4 mm, but very important processes take place inside this tiny organism. In the fifth week, sensory organs are formed. Think about this if you are planning to terminate your pregnancy. The foundations of the gastrointestinal tract and circulatory system are laid. The formation of the little man's face has already begun.

6th week of embryo development

Another important milestone in your baby's development. By the end of this week, the division of the heart into chambers will be completed. It’s only the second month of pregnancy, and the atria and ventricles are already forming. The digestive system is also improving, the liver and pancreas are already fully formed and are completing their development.

In addition, the brain is now actively forming and developing. At this time, it is very important to eat properly so that the baby’s body does not lack microelements. Facial muscles are actively developing. The upper limbs change, they become similar to those that we are used to seeing in newborns.

From the seventh to the eighth week

Now the expectant mother is already interested in what is happening in her tummy, and the best reference is a table of embryo development by week. It is especially interesting to study each week only the information that relates to the current stage. This way you go the whole way with your baby.

In the seventh week, the formation of the umbilical cord is completed. Now until birth, the baby will receive nutrition from her. Now the little man has grown up, he is already 15 mm in length, he can open his mouth and even make the first movements with his hands. Eyes and fingers are formed, the brain is growing and developing rapidly. By the beginning of the eighth week, the fetus begins to straighten. The baby’s face becomes completely human, the nose and eyes, ears and lips are already formed. What previously connected us with distant ancestors, namely the membrane between the fingers, is already lost at this stage of development.

Third month

Another important milestone is the development of the embryo at 9 weeks of pregnancy. At this stage, the fetus is actively growing and gaining strength. The mass is rapidly increasing, and soon he will become quite similar to a small person. Now the baby is actively learning to clench his fingers and make various movements. Another important point characterizing the development of the embryo (9 weeks) is the formation of the endocrine system. The endocrine glands begin to produce their secretions, and the body now produces norepinephrine and adrenaline. The baby may already experience various emotions.

Continuing to look at the development of the human embryo week by week, we smoothly move on to week 10. The embryo is in a fairly free position in the uterus, right now it has a sucking reflex. Despite the fact that the baby is still very small, he can not only make chaotic movements, but also consciously react to external stimuli. He turns his head, moves his fingers and pushes to the side. Therefore, now you can and should communicate with your baby.

The eleventh week is coming. Considering the development of the embryo by week of pregnancy, we cannot help but note this stage, because the placenta has reached its full development and independently provides the supply of nutrients and oxygen, removes metabolic products and carbon dioxide. At this time, the child’s eyes quickly change, an iris appears, which is responsible for their color, although even after birth they will be blue for some time, like all babies.

The twelfth week will please the mother with one more event: now the first breathing movements appear. The chest begins to prepare for the respiratory function while in an aquatic environment. The digestive and nervous systems continue to develop, and now the development of the reproductive system according to the female or male type is clearly visible.

Fourth month

The first trimester of pregnancy has come to an end, the most difficult and dangerous, since most miscarriages occur at this moment. During the first three months, all vital organs and systems were laid down; now they will only grow and develop. And we will continue to look at the stages of embryo development week by week, so that you can get information about what happens to the baby at later stages. Now it’s not yet at full strength, but the entire digestive system is starting to work. Even the intestines, in which the production of original feces, which is commonly called meconium, is included in the work. Your baby has already grown significantly, his length is about 11 cm, and his weight is only 28 g.

Fourteenth and fifteenth weeks

All stages of the development of a human embryo week by week are very important, since the baby in a short time goes from one cell to a complex organism, and all this miracle happens in just 9 months. These two weeks are characterized by the continuation of the development of all organs and systems that are already fully formed. Now not only the kidneys, but also the entire excretory system are involved in the work. The baby begins to produce urine and pee. Now the changes that the brain undergoes are clearly visible. The formation of hemispheres, convolutions and furrows continues. It is at week 15 that the baby’s endocrine system begins to produce hormones for the first time. The thymus gland and adrenal glands are directly involved in this process.

Embryo 16 weeks: fetal development

The fourth month of pregnancy ends. First-time mothers will soon feel their baby moving for the first time. A smile appears more and more often on a small face, hair, eyebrows and eyelashes begin to form. The external genitalia are now fully formed. It is at this stage that the ultrasound specialist will be able to reliably tell you who you are expecting: a boy or a girl. However, it happens that the child turns away or covers himself with his hands. Then you will have to wait to determine gender until the next screening.

Fifth month

Now you can rest assured that your baby hears and understands absolutely everything that happens around him. At various sharp sounds, he begins to actively move, so you can slowly open up the world of music and sounds for him. Spend more time in the forest, in nature, and turn on classical music. The fruit changes its position to vertical. The heartbeat becomes clear, and a woman can already determine how her baby’s heart beats without a stethoscope.

Continuing to consider the stages of embryo development week by week, we move on to the eighteenth. The woman still lives in her usual rhythm, goes to work, but the growth of her baby does not stop for a minute. It is at this time that the pancreas and thyroid glands, as well as the pituitary gland, begin to work. The coordination of the baby’s movements also continues to improve; he is already dexterous enough to push off from the walls, but at the same time, his body size still allows him to travel in the womb. Every day the woman feels these movements more and more clearly, which gives the expectant mother a lot of joy.

The nineteenth week is the period when the baby begins to express his own attitude to the world, he smiles or squints with pleasure, and if he is dissatisfied or offended with something, he curls his lips. Now the baby feels your mood more than ever, so if the mother is upset or excited about something, this will definitely affect the baby’s mood. In addition, the vestibular apparatus begins to form, which is responsible for the position of the body in space.

The twentieth week ends the fifth month. You have already passed more than half of the journey, the golden stage of pregnancy is ahead. Toxicosis and fear for the child’s life are already behind us; at this stage, miscarriages occur much less frequently. The baby begins to play with his mother, constantly reminding him of his presence with active movements. But at the same time, his body weight is not too large, and his mother does not yet experience serious discomfort.

Sixth month

Considering the stages of embryo development week by week, it is necessary to note further important events. Let's see what happens to the baby in the sixth month. By 21 weeks, his weight is already about 300 g, and his height has reached half the length of the newborn’s body - 25 cm. The doctor calmly listens to his heartbeat. Now the child spends more time in a state of wakefulness. By week 22, the cardiovascular and respiratory systems, as well as breathing and swallowing reflexes, become much more advanced. The baby constantly swallows amniotic fluid and increases the frequency of breathing movements.

By the beginning of the 23rd week, the sensory organs complete their formation. The child already sees well, he reacts to bright light, squints if the sun or a lamp shines on the woman’s stomach. Loud sounds frighten the baby, so it is better to avoid noisy public places. During this period, the emotional connection with the mother becomes closer, the child experiences all the emotions that a woman experiences. The baby sleeps approximately 16 hours a day, but the period of his wakefulness will not go unnoticed by the mother.

Seventh month

Now if the baby is born, it will be quite viable, albeit premature. However, normally pregnancy runs its course, and we will continue to look at the development of the human embryo week by week. At week 25, the baby continues to grow, body weight increases and the layer of subcutaneous fat grows. Important processes take place in the lungs: lung tissue appears here and the production of a special substance, surfactant, begins. The lungs are ready to begin their gas exchange functions.

The 26th week is approaching, the baby has already taken on the appearance familiar to a newborn. Now the time has come for the active growth of muscle tissue, while the bones are strengthened and the rudiments of teeth are formed. In addition, another important event occurs this week: the world of smells opens up to the child.

The twenty-seventh week becomes the final week for the formation of individual metabolism. The body can now regulate body temperature. Already at week 28, functional asymmetry of the brain is established, that is, if the left hemisphere becomes dominant, then the child will be born right-handed, and vice versa.

Eighth month

At week 29, the baby is already so consciously performing various movements that he can not only suck a finger, but also scratch behind the ear, stick out his tongue or smile. It is very interesting to observe him using a modern ultrasound machine. The brain and metabolism continue to actively develop. At week 30, the circulatory system improves, and the immune system begins to work. It is thanks to this that antibodies are produced in the blood, which will help protect the body from a variety of infections. The child's height at this stage is approximately 36 cm and weight is about 1.2 kg.

At week 31, the child’s functioning of all organs and systems improves, and the brain and metabolism continue to actively develop. The endocrine system actively produces hormones; they regulate metabolism, as well as the baby’s sleep and wakefulness patterns. In addition, a special hormone begins to enter the mother's blood, which stimulates the production of estrogen. It is thanks to him that the mammary glands begin to prepare for milk production. Finally, at 32 weeks the baby turns head down. It will remain in this position until the end of pregnancy.

Ninth month: from 33 to 36 weeks

No matter when your baby is born, he is completely ready to function independently. At week 33, the brain completes its formation, all internal organs work as a harmonious organism. At this time, the skin becomes light, and the nails have almost acquired a normal appearance. The baby's lungs are fully formed, and when premature labor begins, he will not be much different from children born at 37 weeks.

At 34 weeks, the baby's hair begins to grow rapidly. The bones of the skeleton are also strengthened, which is why mom needs more calcium. By the beginning of the 35th week, the embryo has already reached a height of 42-46 cm, and its weight is about 2500 kg. The liver begins to work intensively, it accumulates iron reserves. By the 36th week, the baby takes a position in the uterus that ensures maximum free passage through the birth canal. The head is bent, the limbs are compressed - this position is due to nature, so the baby accepts it, obeying the biological clock. The bones of the skull become soft. This is necessary for normal childbirth. But all the other bones are already fully formed. By the end of the week, intrauterine development is completely completed, and now the embryo is ready to be born at any moment.

From 37 to 42 weeks

Things for the maternity hospital should already be collected, since the baby can be born at any moment. Now the child is only accumulating subcutaneous fat, becoming more and more like those plump babies they like to show in videos. Doctors believe that birth on any day during these five weeks is normal. Only if the period exceeds 42 weeks will doctors resort to drugs that induce labor. The expectant mother needs to rest as much as possible, as difficult times will soon come. At this time, the baby moves quite little, there is not enough space for him, and the position is not conducive to activity. As soon as the uterus begins to contract, painful sensations appear, you need to go to the hospital, where doctors will provide the necessary assistance.

So, we looked at the main stages of human embryo development week by week. We hope this material will give you the necessary information about your future baby.