What develops in the fetus by week of pregnancy. Development of the child in the womb, changes and tips for weeks. Feelings of a young mother
Pregnancy is a physiological process in which a fertilized egg develops in the uterus, first called an embryo, and later a fetus. The duration of pregnancy is about 9 astronomical or 10 obstetric months. Traditionally, the development of pregnancy is considered by trimesters. However, knowing how the embryo develops by week is also of interest.
Embryo or fetus?
In medical science, you can often find two concepts related to the period of bearing a child - "embryo" and "fetus". What's the difference between them?
Intrauterine development of the fetus is conventionally divided into two stages:
- Embryonic - lasts the first eight weeks. At this time, the fetus that develops in the uterus is called an embryo.
- Fetal (from 9 weeks until the moment of delivery). At this stage, the fetus is in the mother's womb.
How the child will develop, his internal organs, systems, at various periods of intrauterine development of the fetus is determined by the genetic code that was transmitted by the sex cells of the mother and father.
1-10 weeks
1 Week
Speaking about the first week of pregnancy, it should be clearly understood what exactly is taken as a starting point. If we talk about obstetric weeks (regardless of whether the pregnancy is multiple or not), then the first day of the last menstruation of the cycle when the woman had unprotected intercourse and, accordingly, conception occurred is taken into account.
Sometimes the moment when contact occurred without the use of contraceptives is taken into account. Counting by days, get the third obstetric week. If we take into account the date of the beginning of the delay of menstruation, they get the fifth. In gynecology, analyzing the intrauterine development of the fetus by weeks, they are more often guided by obstetric terms.
The first few days, even if it is a multiple pregnancy, are not characterized by any clear signs. This time is the beginning of the menstrual cycle. HCG level ( chorionic gonadotropin human) within the normal range (5 IU / ml for non-pregnant).
HCG fluctuations at the first stage are evidence of:
- a previous abortion or miscarriage;
- taking hormonal drugs.
2 weeks
This time is marked by the fact that the maturation of the zygote continues in the uterus or fallopian tube, which, under favorable circumstances, will become a developing pregnancy.
Towards the end of this period, there comes a time when, after conception, the egg is attached to the wall of the uterus.
This can be indicated by discharge, similar in consistency to egg white and even bloody. A small discharge of blood is a relative evidence of the attachment of an egg to the wall of the uterus, the appearance of an embryo. Abundant discharge during this period of pregnancy is not the norm.
3 week
It was at this time that it can be argued that conception occurred. The fetus is extremely small, its size is 0.15-0.2 mm in length, and its weight is only 2-3 micrograms. If fertilization does not occur, a woman may start her period a few days earlier. When maintaining a special calendar, it is easy to notice a slight shift.
If the pregnancy was planned, significant bloody issues can talk about the threat of miscarriage.
4 week
The embryo develops so actively that a woman may begin to feel the first signs of her changed status, especially if the pregnancy is multiple. There is swelling of the mammary glands, the nipples become sensitive. Menstruation is delayed, sometimes scanty spotting is observed.
At this time, there is an increased risk of fetal anomalies due to excessive physical activity, infectious disease accompanied by high fever, alcohol abuse.
The level of hCG rises only in the blood. On ultrasound, you can see the corpus luteum, which provides nutrition to the fetus before the placenta begins to fully function, and is also involved in the production of progesterone, the so-called pregnancy hormone.
The size of the embryo increases. It is already 5 mm long.
The fruit weighs 3.5 g, and the length is from 4 to 7 mm. The rudiments of limbs, fingers, eyes, auricles, slits for the nose and mouth, some glands and systems begin to form in him. The size of the uterus changes.
An ultrasound specialist at this time can tell if a woman is developing a multiple pregnancy or if she will have one child. During the examination, the diameter of the fetal bladder is established, as well as the coccygeal-parietal size, the “growth” of the fetus. The last figure will appear in the results for the entire first trimester.
Changes in the body become more noticeable. Some women report a slight increase in body temperature to subfebrile levels. However, if the condition begins to fall under the description of a cold, you should immediately consult a doctor.
6 week
The woman begins to show signs of future motherhood. The uterus reaches the size of a plum - an experienced gynecologist is able to probe it during the examination. Under the condition of multiple pregnancy, ultrasound will show two fetal and yolk sacs. And the examination will also allow you to see small tubercles - here, over time, the upper and lower limbs will appear, and you can also hear a heartbeat on a special apparatus. Facial features gradually emerge. The embryo reaches a length of 4-9 mm, its weight is not more than 4.5 g.
7 week
The fetal heart becomes four-chambered, large blood vessels form. The first trimester is marked by the continuation of the development of all internal organs and systems. Weight - 1 g, coccyx-parietal size is 13 mm. The unborn child gradually begins to straighten up. The brain is developing rapidly.
The face, upper limbs are being improved. The umbilical cord completes its formation, a mucous plug forms.
The size of the fetus increases significantly - 14-20 mm in length, it begins to move. By the middle of the first trimester, the face acquires more and more human features. The laying of organs and systems has been completed, some of them are actively functioning. The optic nerve is born, the rudiments of the genital organs appear.
9 week
The coccyx-parietal size of the unborn child reaches 22-30 mm, weight - 2 g. active formation cerebellum, pituitary gland, middle layer of the adrenal glands, lymph nodes, genital organs. The work of the cardiac and nervous systems is improved. The upper and lower limbs begin to move, bend, muscles appear. The fetus develops the ability to urinate.
For the fetus, the critical first stage of development ends. Weight reaches 5 g, and height - 30-40 mm. The heart rate reaches 150 beats per minute. The limbs are fully formed, you can see the joints and fingers. The foundation of milk teeth is being laid, which obliges the mother to keep a food calendar and mark the consumption of dairy products in it. Most of the organs of the gastrointestinal tract have already completed the formation.
11-20 weeks
11 week
The critical stage of development is actually over. The weight of the fetus reaches 8 g, "height" - 5 cm. From this moment, the embryo passes into the fetal stage. The heart works fully, the formation of blood vessels is completed. The placenta becomes dense. The liver occupies 10% of the body. The intestine makes the first movements similar to peristalsis.
More and more formed genitals. The color of the eyes is determined, the sense of smell appears. Palms and fingers become sensitive.
12 week
Critical moments for the development of the fetus are more dependent on the health and lifestyle of the mother. The body length ranges from 6-9 cm. The unborn child already has fingers, nails are formed. The organs of the gastrointestinal tract are completing their formation. The immune system improves.
The first trimester ends, the critical cycle is completed. Milk teeth are completely laid down, muscle and bone tissue continues to take shape, and the digestive system develops. The sex organs are differentiated. The "growth" of the child reaches 8 cm, weight - 15-25 g.
14 week
The baby is actively growing and developing. Its weight is 30-40 g, and its height is from 8 to 10 cm. The resemblance to a person is more and more. Under the condition of multiple pregnancy, the expectant mother can feel the movements of the children, who are becoming more active. The bone skeleton grows, ribs are formed. Diaphragm movements are reminiscent of breathing. All organs and systems are fully formed. The child has an Rh factor and a blood type.
Starting from the 15th week, the child's cerebral cortex begins to form. The process will take most of the second trimester. Activated endocrine system, sebaceous, sweat glands.
Taste buds are fully formed, respiratory movements are improved. The weight of the child reaches 70 g, from the coccyx to the crown of the head it is already as much as 10 cm. But even under the condition of multiple pregnancy, this does not interfere with free movements.
16 week
By the first half of the second trimester, the baby is already 11 cm tall, and weighs 120 g. The neck has taken an even position, the head rotates freely. Ears and eyes gradually rise up. The liver takes over the digestive functions. The development calendar is getting busier. The composition of the blood is completely formed.
The immune system turns on, interferon, immunoglobulin is produced. The baby is able to defend itself against infections coming from the mother. But all of them continue to be critical for a small organism. The fetus has a fatty layer. If a girl grows, by the middle of the second trimester she will have a uterus. A person's height is 13 cm, weight is 140 g. He is able to hear sounds from the outside, to feel emotions. From the point of view of emotional and mental development, the 17th week is critical - it is extremely important to establish contact.
The second trimester is approaching the middle. The upper and lower limbs of the fetus, phalanges of the fingers, and prints on them are fully formed. Adipose tissue, the immune system and the brain continue to develop actively at week 18. The rudiments of molars are formed.
There is a reaction to light, hearing is enhanced. The calendar should be sure to enter the date of the first movements, their frequency. Fetal height 14 cm, weight - 200 g.
There is a big leap in development. Movements become more streamlined. The respiratory system is improving. The body is covered with primordial lubrication. By week 19, the head rotates freely, is held in one position. Weight reaches 250 g, and height - 15 cm.
20 week
The child is already fully formed, his organs are being improved. By week 20, the heartbeat can be heard with an ordinary stethoscope. Limbs are fully formed. Sound sensations become more acute. The length is 25 cm, and the weight is about 340 g. The movements are more noticeable for the mother.
21-30 weeks
By week 21, the baby adds in height - 26.7 cm and in weight - 360 g. But there is enough space for active movements. The digestive system works more actively, the fetus constantly swallows amniotic fluid. Muscle and bone tissues are strengthened. The spleen is included in the work of the body.
22 week
The period is marked by a significant increase in weight - up to 500 g. The height also changes - as much as 28 cm. The fetus at these times is viable even if it is first born. The brain and spine are fully formed. Improved reflexes. The heart is enlarged.
23 week
By the 23rd week, the fetus is sufficiently formed, the digestive system is fully functioning. Accumulation of adipose tissue. The genital organs are clearly differentiated.
The growth of the baby reaches 29 cm, and the weight is 500 g. The spleen becomes more active.
Outwardly, the fetus already looks like a child. Because of a small amount adipose tissue weighs only 600 g with a height of 30 cm. By the 24th week, independent production of growth hormone begins.
The respiratory system enters the final stage of development. Improved reflexes, sense organs. Sleep and wake patterns are developed. The baby begins to listen to the emotions of the mother. The movements become sensitive.
The fetus recovered to 700 g and grew to a mark of 34.5 cm. The resemblance to a newborn is increasing.
The lungs prepare for the first spontaneous breath. The function of hematopoiesis is completely taken over by the bone marrow.
The sense of smell is highly developed, the child feels the mood swings of the mother. The bone skeleton is actively overgrown with muscles. Testicles and vagina appear.
The fruit takes on a personality. The eyes begin to open. The child is able to recognize the voice of the mother and father. The bone tissue is strengthened. The lungs finally take shape. The brain produces various hormones. The baby weighs 750 g, it is as long as 36.5 cm. Sleeps 16-20 hours. Movements can be seen by others.
27 week
900 g of weight has a fetus by 27 weeks. Growth is getting stronger. The endocrine system also enters a new phase of activity. The stability of the child's pancreas determines the development metabolic processes, mental abilities. The production of surfactant - a substance that ensures the opening of the lungs after birth - stabilizes.
The amount of subcutaneous fat increases. Mom feels the baby’s training even more strongly.
Bone tissue continues to strengthen. Alveoli appear. The future little man can weigh 1 kg or more. Having reached a height of 38.5 cm, the baby begins to feel a lack of free space in the uterine cavity, although this does not affect his activity in any way.
29 week
The baby's body is gradually preparing for the upcoming birth. Thermal regulation is established, work immune system. Stabilized blood composition. The digestive system is fully prepared to digest food. The gaze begins to focus. The skin gradually brightens, loses wrinkles. Subcutaneous fat grows, muscle tissue becomes stronger.
30 week
The weight of the child reaches 1500 g. Gradually, the nervous system “turns on”. The liver stores iron. The work of the heart acquires sexual differentiation - in boys it beats more calmly than in girls. As a rule, by this time the fetus is in the position from which it will be born. Movements become more relaxed. The eyes are open.
31-40 weeks
A child can already weigh more than 1.5 kg. The liver acquires the ability to purify the blood.
Surfactant production continues. Establishes communication between peripheral nerve cells and the brain. Touching the cornea, the baby will definitely close his eyes. The intrauterine development calendar is gradually coming to an end.
32 week
The active growth phase continues. Organs and systems are fully functional. Skin and appearance take on a familiar look. Gradually disappears lanugo - the original fluff.
The baby finally takes the position for childbirth. The skull remains soft.
At this time, the weight reaches 2000. Muscles and subcutaneous fat continue to grow. Parts of the body become more proportional, many body systems work fully. The child is able to express emotions. The kidneys are preparing for their main function - filtering.
34 week
The development of the fetus is coming to an end. Individual traits are becoming more pronounced. Training of the gastrointestinal tract are more active.
By these days, organs practically do not develop. Activity is observed in terms of building muscle and adipose tissue. Every week, the baby gains up to 220 g. The skin is deprived of lanugo, completely smoothed out. Shoulders are rounded.
The body continues to improve. Iron continues to accumulate in the liver, vital systems are debugged. The baby actively sucks his thumb in preparation for the upcoming breast sucking. Most of the children are occupied, that is, head down.
37 week
The fetus is fully formed. The gastrointestinal tract is ready to receive, digest food, peristalsis is activated. Heat transfer processes have been established. Light ripe. Iron accumulates in the liver. Height and weight increase weekly.
The baby is ready to be born. In male children, the testicles descend into the scrotum. The skin becomes rosy.
The fetus is fully formed, its organs and systems are ready for independent functioning. Developed response to sounds, light. There is no original lubrication on the surface of the skin.
40 week
The height of the baby is approximately 54 cm, weight - from 3 to 3.5 kg. Formation is complete.
Reading 11 min.
The stages of development of a child in the mother's womb are called trimesters, each of which is marked by intense transformations in the body of the fetus and its structure. The duration of the trimester is 90 days. During this time, the child manages to reach a new level of development. Consider the development of a child in the womb and their key features by weeks.
The development of a child in the womb on the example of a mannequin
Baby development in the first trimester
The first trimester of pregnancy begins at conception and lasts up to 15 weeks on average.
1 Week. The body is preparing for future motherhood. The body actively creates conditions for the most comfortable conception, and a little later - the development of the child in the womb of his mother. In the next two weeks, the body will need to form a prototype of the unborn child.
The structure of the genital organs and the conception of a child Tips: if possible, refuse to take medicines, with the exception of those prescribed by the doctor and gradually accustom yourself to healthy lifestyle life - with regular walks, moderate physical activity, proper nutrition.
Smoking, alcohol and coffee starting from this period must be abandoned. Additionally, to prevent the development of fetal malformations, pregnant women are advised to drink folic acid regularly.
First week after conception 2 weeks. Changes in the reproductive organs of a woman become more obvious, a slight pulling pain may appear in the lower abdomen. The hormonal background begins to change under the influence of the developing corpus luteum. The egg is still preparing for fertilization.
Tips: The period from the end of the second week to the beginning of the third is ideal for subsequent conception.
Phases of the menstrual cycle favorable for conception In order to increase the likelihood of pregnancy, a few days before the onset of ovulation, it is best to take a short break in sexual activity - this will allow sperm to accumulate.
3 weeks. During this period, conception itself occurs. Changes affecting the body of the expectant mother become even more pronounced.
Tips: for the safety of the child by these weeks, it is best to minimize contact with harsh chemicals, sources electromagnetic influence. Avoid x-ray examination of the abdominal cavity.
4 weeks. During this period, implantation occurs. The woman also stops menstruating. The body of the child does not yet have a distinct outline and rather resembles a disk of three layers of tissues, from which the skin, skeleton, internal organs, etc. will subsequently develop.
5 weeks - photo and ultrasound Tips: during this period, it is extremely important to protect yourself from overheating. An increase in temperature can have an extremely negative impact on the health of the unborn child.
5 week. The development of the embryo occurs intensively, due to which the outlines of the body, well-marked limbs are formed in the child, and the head stands out. The foundations of the future nervous system are being laid.
Tips: For better development of the baby's nervous system, mothers are advised to take folic acid.
Folic acid reduces the risk of miscarriage Also, during this period, pregnant women need healthy sleep and rest more than ever - due to ongoing hormonal changes, she may begin to feel symptoms such as increased fatigue and irritability.
6 week. The child's brain is improving; he begins to gradually coordinate the work of the heart and skeletal muscles. Blood cells begin to form in the liver. The child already has the rudiments of most of the internal organs. The placenta grows, providing the baby with the nutrients necessary for growth and development.
Tips: during this period, dizziness and toxicosis may increase. In order for the unpleasant symptoms not to bother the woman so much, it is recommended to always have some salty crackers and water or juice with you (this will relieve nausea).
7 week. The features of the child's face become more distinguishable - he already has clearly visible auricles, jaws, eyelids, giving the child the opportunity to independently open and close his eyes. The child makes movements that are not yet felt by the mother, but are quite noticeable. The child's heart is already divided into 4 chambers, the largest blood vessels are formed.
Week 7 - the beginning of the formation of the body Tips: for the full development of the child, a woman is recommended to eat foods rich in B vitamins. You can cope with toxicosis by eating often and in small portions.
8 week. The internal organs of the child are functioning quite actively - his heart is beating, the stomach and kidneys are actively working. The brain effectively organizes the activity of organ systems, the level of development of the nervous system already gives the child the opportunity to respond to their external conditions with the help of facial expressions. The skeleton is being improved - fingers and joints become clearly visible. The Rh factor of the child becomes clear.
Tips: you need to protect yourself from increased stress - both mental and physical. In order to better control the course of pregnancy, it is also desirable to find a doctor who will accompany the woman until delivery and give her valuable guidance.
9 week. This week is characterized by intensive development of the brain, especially the cerebellum, which is responsible for the coordination of movements. The child's eyes are already well formed, but covered with a membrane that does not allow them to see what is happening around. The limbs are strengthened. The fingers are already well distinguishable, but are interconnected by a membrane.
9 weeks - fingers appear Tips: starting this week, you need to choose underwear that provides the body with proper support. It is best to reduce the load on the abdominal muscles. To prevent weakening of the veins, you can take preparations containing vitamins C and P.
10 week. During this period, the reproductive system of the child is most actively formed. The remaining vital organs are already well developed.
10 weeks - the body is fully formed Tips: during this period, the mother needs foods rich in calcium - this will protect the bones and teeth from destruction.
11 week. At this time, the brain develops most actively and intensively: due to this, the head of the child is much larger than the body. The intestines and kidneys begin to work.
11 weeks - the baby begins to move Tips: At this time, it is advisable to start saving money for the upcoming maternity leave. This will avoid many problems in the future.
Special care should be taken about the skin - it can become drier and will begin to require more intense hydration.
Foods rich in calcium contribute to the proper development of the baby's skeleton 12 week. The child is already quite energetic - he actively interacts with the outside world and reacts to external stimuli - light, sound (for example, he can close his eyes with his palm, or cover his ears with his hands). A fairly good level of development of the cerebellum and the vestibular apparatus allows him to navigate well in space. Movements become more diverse: the child already knows how to make simple movements with his fingers, make head turns.
13 weeks - the brain is actively developing Tips: if possible, it is necessary to avoid food poisoning, as well as conditions that provoke a state of hypoxia (intense physical exertion, hiking, etc.).
15 weeks - baby on ultrasound Child development in the second trimester
Highlighting time intervals in development, we note that the stages of development of a small child in the womb of his mother are quite difficult to distinguish between weeks or months. However, from about 16 weeks, the second trimester of pregnancy begins, which has its own distinctive features.
16 weeks - photo 16 week. The child develops sucking and swallowing reflexes. His eyelashes and eyebrows are already clearly visible, he is learning to smile. The placenta, which connects mother and child, is already functioning quite actively. Growth is already 16-18 centimeters, weight - at least 150 g.
Tips: get tested for possible malformations of the child (recommended blood test for alpha protein, hCG hormone and unconjugated estriol). To improve the general condition of the body, you can go swimming.
20 weeks - the first portrait of the baby 20 week. The baby's heartbeat is already clearly audible with a stethoscope. Nails are formed on the fingers. Thanks to the good development of the musculoskeletal system, the child can already actively move inside the uterus and the woman already feels his movements inside herself. The child's reactions to light or sound become more diverse.
Swimming is very beneficial for pregnant women Tips: It is very important to protect your back from unnecessary stress. Yoga, massage, physiotherapy exercises can help get rid of discomfort.
21 weeks - mom already feels the movements of the fetus 24 weeks. The child's lungs are actively developing, the sweat and sebaceous glands begin to work. the skin has a slightly reddish tint; amniotic fluid protects it from mechanical damage. The child's behavior also acquires new features - he can get angry and express his dissatisfaction, he can cry. Periods of wakefulness alternate with periods of sleep, and during the latter the child begins to dream.
Supportive underwear will help to avoid stretch marks Tips: Due to the weakening of collagen fibers in the skin on the abdomen and chest, stretch marks can form. In order to avoid this, it is necessary to use a special intensively moisturizing cream.
Child development in the third trimester
The development of a child in the womb of his mother in the third trimester is different in that he has formed almost all vital organs and in the future they will have to actively develop.
28 week. All the senses of the child are already quite well developed. He begins to breathe on his own, the skin thickens. Weight approaches one kilogram. He begins to distinguish the voices of people and distinguish among them the voice of his mother.
28 weeks - the baby is fully formed If we consider the development of the child in the womb of the child's mother by months, by this time the fetus reaches a 7-month period. If during this period the mother begins childbirth, he can survive thanks to the efforts of doctors and his own resources that ensure his life support.
Tips: during this period, you need to visit a doctor more often than before. In particular, among the necessary tests are the level of iron in the blood and glucose tolerance.
A premature baby can be born weighing up to 1 kg In the event that both partners differ in positive Rh factors, another analysis will be required - for antibodies.
32 weeks. Due to the fact that the mother’s body actively transfers immunoglobulins to the child, immunity begins to form in him, which in the future can protect him from many health problems. Thanks to the already well-formed layer of subcutaneous adipose tissue, the child's body takes on a new shape. The amniotic fluid that surrounds the baby is renewed every three hours.
Gymnastics for pregnant women - preparation for childbirth Tips: due to the fact that the child often rests his feet on the ribs, a woman may experience pain in the sternum. You can avoid this by trying to keep your back straight when walking and sitting.
34 weeks. The baby's lungs open and he can breathe on his own. With a height of 40 centimeters, his weight remains about 1700 - 2000 grams, and he continues to gain weight and this dynamics can be clearly seen by weeks. Because of this, he is already cramped in the uterus and he often takes the most convenient position for childbirth - head down.
Tips: during this period, the so-called Braxton-Hicks contractions, which are often confused with prenatal contractions, become quite frequent. In order to clearly distinguish them from each other, it is necessary to consult a doctor regularly.
The difference between false and true contractions If water breaks, call a doctor immediately!
38 week. The child's liver intensively accumulates iron, which in the future will actively contribute to the hematopoietic function. It is growing rapidly, gaining at least 14 grams per day. The position of the child is determined finally. Development in the womb comes to its logical conclusion and the mother focuses on the birth of the child. He is ready for birth and only a few days remain until the moment of birth.
38 weeks - the baby is preparing for childbirth Tips: you need to pay attention to the harbingers of childbirth - pain in the sciatic nerve and contractions.
Newborn baby - cutting the umbilical cord Knowing the features that govern the development of a child in the womb of a woman by weeks and at each stage, you can prepare for each period of pregnancy, providing yourself and the child with everything you need. And at the same time - to create for him optimal conditions for healthy growth and development.
Every mother who finds out about her pregnancy is always interested in how her baby develops in the womb, what happens to him at different stages of pregnancy. It is also curious how the fetus changes in each trimester of gestation. Let's look at how the development of the unborn child is going on by weeks of pregnancy.
Period up to 8 weeks
So, what does the fetus do for 9 months in the mother's womb? Let's start from the very beginning, from the moment the egg is fertilized by the sperm. By the way, up to 8 weeks, the fetus is called an embryo. During this period, all its systems and organs are formed.
After fertilization, the egg begins to split. It moves in the direction of the uterus and is released from the shell. The introduction into the uterus (attachment of the fetal egg) occurs on the 6-8th day after fertilization. The process of attachment occurs with the help of chorionic villi.
At 2-3 weeks, the embryo develops very actively: the foundations (rudiments) of the muscular, bone, and nervous systems are formed. That is why the stage of their "bookmarking" is considered an important period of gestation.
At 4-7 weeks, the following organs are formed in the unborn child: heart, head, arms, legs. At week 5, the length of the embryo is about 6 mm. During the period of 7 weeks, the rudiments of the eyes, abdomen and chest begin to be determined in him, and fingers form on his hands. At this time, the embryo already has a vestibular apparatus (sense organ), and its length increases to 12 mm.
At week 8, the process of determining the face begins. Then you can already distinguish between the mouth, nose and auricles. If we talk about the overall size, then the head of the embryo is very large and the body is not proportional. All its elements are already formed, and the nervous and musculoskeletal system are being improved. The sensitivity of the skin in the mouth area also appeared during this period, thus preparing for the formation of a sucking reflex. At the same time, the genitals are also visible. The fruit is approximately 20 mm long.
Fetal development up to 18 weeks
At week 9, the fingers of the unborn child on the hands and feet already have nails. He begins to move in the womb, but the mother does not feel these movements, because the fetus is small and a large number of places in the uterus are occupied by amniotic fluid. The doctor can already hear the baby's heartbeat with a special stethoscope. At this time, the process of muscle development continues, so the baby touches himself, his body. This is an interesting process that can be observed on ultrasound. And first of all, the child reacts to the touch of the sensor. He pulls away from him at first, and then tries to put his hands on him, trying to touch the sensor.
At the 11-14th week of pregnancy, the child's arms, legs, eyelids are already clearly formed, the genitals become visible. That is, on ultrasound, you can find out the sex of the unborn child. During this period, the fetus already "knows how" to swallow. And even if he didn’t like something, he can frown, stick out his tongue as a sign of discontent. The skin at this time has a transparent appearance.
At week 14, blood forms in the middle of the bones, hair growth begins on the head, and the baby himself already moves more clearly and coordinated.
15-18 weeks in the development of the fetus is characterized by clearer facial features, pinking of the skin, the ability to open the mouth, blink, grab the handles. During this period, the fetus is more active in the womb.
19-23 weeks of development
A child at 19-23 weeks of pregnancy can already suck his finger, in his intestines there is already a pseudo-feces, which is called meconium. The kidneys begin their work, and the brain develops very actively. During this period, the process of ossification of the auditory cartilages takes place, and the child can already hear his mother: her breathing, heartbeat, voice. The lungs are developed in such a way that, under force majeure circumstances, the child will be able to survive in intensive care.
This period is the equator of pregnancy, the period at which a woman first feels the baby move. This date must be remembered and reported to the gynecologist.
Significant weight gain, the formation of fetal fat is also characteristic of this period of pregnancy. Weight at 23 weeks is approximately 650 g, height - 300 mm.
24-32 weeks of fetal development
The lungs of the fetus continue to develop until 32 weeks. The child falls asleep, wakes up. His skin becomes wrinkled, it is covered with grease. The sensitivity of the lips and mouth increases, the eyes open slightly, perceive light and even squint. The development of the fetus up to 32 weeks is characterized by the adaptation of the lungs to breathing ordinary air. The breathing process itself is already rhythmic, the baby reacts to external stimuli. The skin is significantly thickened, becomes smoother, pinker. From this period begins a period of intensive growth and weight gain. Most children born at this time survive. According to statistics, this figure is 9 out of 10. The weight of the unborn child at 32 weeks is about 2500 g, the length is 450 mm.
33-37 weeks of fetal development
At this time, the baby clearly reacts to light. He is already able to turn his head, raise it. His hair becomes silky. At 33-37 weeks, a grasping reflex develops, and the lungs are already fully formed and ready for independent “work”.
At 37 weeks, the fetus is ready to be born. Every day he gains 30 grams of fat, a protective sheath forms around his nerves. The cartilages of the nose and ears harden during this period. If this is the first pregnancy for a woman, then, as a rule, she nurses until the end of the term.
Fetal development from 38 weeks to birth
The baby in this period is already considered mature. He has well developed more than 70 types of reflex movements. His skin is pale pink due to a sufficient amount of subcutaneous fatty tissue. The skin on the head is covered with hairs up to 3 cm long.
The baby already clearly captures the mood of the mother. When she is calm, calm and he, when, for example, the mother is worried or in a noisy company, the child can protest with active movements.
The nails already protrude beyond the tips of the fingers, the cartilages of the ears and nose are quite dense and elastic. In boys, the testicles have already descended into the scrotum. In girls, the small labia are covered with large ones. The weight of the child during this period reaches 3600 g, the length is about 520 mm.
After birth, the baby perfectly remembers the rhythm of his mother's heartbeat. That is why you can soothe a crying newborn with an ordinary attachment to the chest in the region of the heart.
Patience to you, future mothers, health and optimism!
Specially for Elena TOLOCHIK
The appearance in the family of a child- the desired and very exciting moment for which young parents begin to prepare, barely learning about the pregnancy. Therefore, information regarding the development of the fetus by months of pregnancy is always very important and informative. In addition, the birth of a new life and the development of a small person will also be of interest to people who have not yet thought about procreation, since nature provides for a simply unique process. It consists of three stages: first, second and third trimester, during which the formation of the child occurs.
First months of pregnancy- the most important for the further development of the fetus, because right now the fertilized egg joins the wall of the uterus and slowly begins to turn into a child. 
Whether it is fixed or not, and how correctly the further formation of all systems of a small person will take place depends on a number of factors. We will try to understand the features of this process weekly.
First week (1-7 days)
You can talk about the beginning of pregnancy when a male cell (sperm) fertilizes a female egg, this is talked about even in biology classes at school, but what happens next is not studied in detail.
Most often, this process occurs in the fallopian tube (in its ampullary section), but already a couple of hours after the “meeting”, the fertilized egg quickly begins to divide, and then descends into the uterine cavity through the fallopian tube. This entire process takes approximately five days. 
As a result, a multicellular organism appears in the uterus, somewhat reminiscent of a blackberry (in Latin "morus"), from which the embryo at this stage received the name "morula".
On the seventh day it is introduced into the uterine wall, and the villi of its cells (external) are connected to the blood vessels of the female organ, which later form the placenta.
The remaining outer cells become the basis for the development of the membranes of the embryo and its umbilical cord. As for the internal cells, they become the beginning of the internal organs of a small person.
Important! When the egg is attached to the wall of the uterus (implantation), a woman may experience bloody discharge from the vagina, but this is quite normal and should not be worried.
Second week (8-14 days)
The cells of the embryo continue to grow into the uterine mucosa, after which not only the placenta, but also the umbilical cord and the neural tube begin to form. very important component, from which the nervous system of a new person is subsequently formed.
During this period, there should be no any heavy bleeding, because their presence indicates the possible presence of a disease, for example, endometrial hyperplasia or impaired functioning of the ovaries, but a woman may also begin menstruation, which indicates an unsuccessful attempt to become pregnant.
True, it is too early to talk about a full-fledged miscarriage, since the fetus has not yet become such, but for now it is only an egg.
Third week (15-21 days)
One of the most difficult and important periods, since right now all the important systems and organs of the unborn child are starting to form, the respiratory, circulatory, nervous, digestive and excretory systems are being formed, and in the place where the fetal head will soon form, a wide plate appears - the basis for further formation and development of the brain. 
Important feature this week - the beginning of the heartbeat in the embryo. Now we can say with confidence that conception has occurred, although the possibility of a miscarriage should not be ruled out.
Did you know? In the third week of pregnancy, the body weight of the unborn baby is only 2-3 micrograms, and the length of the "calf" is from 0.15 to 0.2 mm.
Fourth week (22-28 days)
The laying and formation of the fetal organs continues, from which the intestines, liver and lungs can be distinguished. The working capacity of the still tiny heart is increasing more and more.
At the end of the first month During pregnancy, the folds of the torso are formed in the embryo, and the spine (chord) is laid, dividing the embryo into two halves with a clear selection of the limbs. On the head of the future baby, pits begin to form, which a little later will become eyes.
Fifth week (29-35 days)
According to the pregnancy calendar, it means the beginning of embryo development in the second month (obstetric).
At that time in a little man (his height from the crown of the head to the coccyx varies between 1.5-2.5 mm), all the organs of the digestive (pancreas and liver), respiratory (lungs, larynx, trachea), sexual (formation of the precursors of the genital cells), nervous (formation of brain parts) systems, as well as further developing sensory organs - the eyes and the inner ear.
Besides, in the fifth week the umbilical cord is already visible and the baby's limbs continue to form, and the rudiments of marigolds form on them. On the front part, the nasal cavities and the upper lip are already distinguishable.
Many women at this time clearly feel pregnancy, because the uterus increases dramatically (outwardly, this is not noticeable in any way) and puts pressure on the bladder. Manifest the first signs of toxicosis and increased sensitivity to various odors.
Sixth week (36-42 days)
By the sixth week, the unborn child reaches a length of 4-9 mm. His heart beats very quickly, although it is still far from a full-fledged organ - no atrium. The placenta is formed, which is just beginning to perform its direct functions, and the blood circulation with the embryo has not yet been established.
Continue be actively formed all parts of the brain, and if you make an encephalogram, you can fix the signals sent by the tiny brain. The formation of facial muscles also begins, the eyes of the embryo become more pronounced and uncovered for centuries.
The upper limbs are slightly elongated, while the lower ones are still in their infancy. In the digestive system, sections of the gastrointestinal tract (small and large intestines, as well as the stomach) begin to form.
The pancreas and liver almost completely complete their formation.
Seventh week (43-49 days)
The length of the body of the embryo is approximately 10-13 mm. The placenta becomes much thicker, and the baby is already firmly connected with the mother by the umbilical cord, along which the uteroplacental circulation is finally formed.
It is noteworthy that the little man still there is a ponytail, which will soon disappear, and the baby's legs remain like small fins, while the upper limbs can already bend at the elbows, the rudiments of the fingers begin to be visible. Shoulders and forearms are clearly distinguished.
Embryo eyes covered with eyelids that protect them from drying out, and the child sometimes opens his mouth. The nose and nasal fold are laid, two paired elevations appear on the sides of the head: from them, the auricles develop later.
It was at this time mucus plug is formed, which will close the cervix and protect the baby from harmful environmental factors.
Eighth week (50-56 days)
The body of the baby gradually straightens and its length (while measured from the coccyx to the crown) corresponds to 20-21 mm (by the end of the week). Continue to form major body systems: digestive, cardiovascular, respiratory (especially lungs), urinary and sexual (testicles begin to develop in boys).
Sweat and salivary glands are still at the stage of formation. The baby’s face also becomes more familiar to an adult: the eyes are well defined, the nasal cavity and auricles are formed, the process of lip formation is completed.
Both the head and all the limbs begin grow rapidly, ossification of the long bones of the legs and arms also occurs. On ultrasound, you can see small fingers, between which there are no membranes. The eighth week is the period of formation of the optic nerve.
Embryo starts to move but because of it small sizes the woman does not feel these movements.
Important! It is on the eighth week that the embryonic stage comes to an end and the embryo is already called the fetus.
Ninth week (57-63 days)
The length of the fetus is in the range of 22-31 mm. The vessels of the placenta continue to improve, the system of bones and muscles develops intensively, in particular, the joints of the legs and arms are formed.
Peculiar changes are noted in the functioning of the cardiovascular system: the heart is already able to make 150 beats (in 1 minute) and pump blood through the blood vessels. The brain is still actively growing and developing, the structure of the cerebellum is emerging, the pituitary gland is being formed. 
Also adrenal glands begin to develop, while producing important hormones for the body, lymph nodes develop. At the same time, cranial, spinal and intervertebral nerves appear.
With an unborn child cartilage tissue is also improved, which is this stage expressed in the design of the auricles, cartilage of the larynx and the formation of vocal cords.
At nine weeks the fetus looks like a small pea pod, which through the umbilical cord removes the products of its vital activity into the mother's body.
Tenth week (64-70 days)
The fetus (from crown to coccyx) has already reached a length of 35-40 mm. The most interesting change is the loss of the ponytail and the shaping of the buttocks, but this, of course, is not the only important change.
Further, the nervous system is improved (already divided into central and peripheral) of the fetus, which can already perform not only chaotic movements, but also shudder in response to a stimulus (the first reflexes are formed).
For example If the baby accidentally touches the wall of the uterus, he may turn his head, bend or straighten his arms and legs, or even push himself to the side. At the same time, the development of the diaphragm comes to an end, which as a result will be directly involved in the breathing process.
With high speed the brain is being formed and in one minute it can create up to 250 thousand neurons.
Eleventh week (71-77 days)
The body of the unborn child at this time still remains disproportionate: a large head stands out strongly against the background of a small torso, and the arms are longer than the legs, bent at all joints and located in a contracted state. By the end of the eleventh week, a fetus 4-5 cm in size is in the womb of a woman.
The placenta at this time already fully performs all the functions assigned to it and provides the little person with enough oxygen and micronutrients. In addition, it is she who pushes out the metabolic products and carbon dioxide. 
The further formation of the baby's eyes is also noticeable, because the iris appears, which as a result will determine its eye color.
appear in the fetal blood first lymphocytes that are directly involved in the formation of immunity.
Did you know? At this stage of fetal development, the liver of the unborn child is 10% of his entire body. The intestines also make their first movements (something like peristalsis).
According to experts, at week 11, the sense of smell of a little man is also formed.
Twelfth week (78-84 days)
Fruit size(from the crown of the head to the coccyx) approximately within 50-60 mm, its genitals (male or female) are actively developing and the digestive system is improving. As for the latter, the most noticeable is the lengthening of the intestine and its loop placement (just like in an adult). 
Baby already can swallow amniotic fluid, squeeze and unclench the fingers on the hands, and also grab the thumb in the mouth and actively suck it. In addition to erythrocytes, leukocytes (white blood cells) also appear in the baby's blood, and single respiratory movements can also be recorded.
Of course, until the moment of birth, the fetus is not yet able to breathe on its own and its lungs do not function properly, but it may well perform rhythmic movements chest.
Did you know? Starting from the 12th week, unique patterns - prints - form on the fingertips of a tiny man.
Thirteenth week (85-91 days)
The size of the future baby reaches about 70-75 mm, and the proportions of his body begin to actively change: the lower, upper limbs and torso become longer, and the size of the head does not seem so large.
All these changes the expectant mother can see on the monitor when undergoing an ultrasound scan, especially knowing in advance about the stages of pregnancy and the developmental features of her child by weeks. 
In addition, the 13th week is also significant for the beginning formation of milk teeth, which are located under the lower and upper jaws.
By the way, crumbs in the intestines first hairs appear, which after birth will be directly involved in the process of digestion and promotion of food. The pancreas produces the first insulin, and the vocal apparatus is also actively formed.
The emotional sphere of the baby also develops who learns to respond to sounds, silence, light and shadow, heat and cold, becoming more and more awake.
Fourteenth week (92-98 days)
By the end of the 14th week, the body of the fetus becomes longer and is already 8-9 cm, and its proportions are becoming more familiar. The first hairs are already visible on the head, however, while they are quite thin and do not have a specific color.
The surface of the body is covered with sparse fluffy hairs.
The bones and muscles of the fetus develop and improve, the first ribs appear, and the development of the bladder, ureters and kidneys, which actively secrete urine mixed with amniotic fluid, is completed. 
Swallowing amniotic fluid, the child can determine its taste by reacting to sweet with rapid swallowing reflexes or weak sips to bitter.
My work starts pancreatic and pituitary cells. In boys, the prostate gland is actively developing, and the ovaries of girls are located in the pelvic region.
If you do an ultrasound quality equipment, then with a high degree of probability it will be possible to find out the gender of your baby.
If we consider in detail the stages of pregnancy by weeks, then starting from the fifteenth, we can talk about the second trimester of pregnancy. Until this time, the fetus has already strengthened in the uterus, all its main systems and organs have almost formed, which reduces the risk of unforeseen situations. 
However, quite expectant mothers should not relax, as there are still a lot of important stages in the development of the baby.
Fifteenth week (99-105 days)
Since the beginning second trimester, the fetus weighs approximately 70-75 g, and its length (still measured from crown to tailbone) is 10 cm. Despite the fact that the baby's head has big sizes, the growth of his limbs and torso begins to outstrip it.
At the same time, if desired, you can find out the blood type of the little man, and he also begins to stand out the original feces (meconium).
Nevertheless, the most important process at week 15 is the beginning of the formation of the cerebral cortex, which will take place throughout the fourth month.
It is also impossible not to remember the activation sweat and sebaceous glands.
Sixteenth week (106-112 days)
At this time, the baby's body length is about 12 cm, and the weight increases to 100 g. At 112 days after conception, the fetus is considered fully formed, since it already has all the systems and organs.
However, the fetal skin is still quite thin, and subcutaneous fat is almost completely absent, which is why blood vessels are clearly visible. Eyebrows and eyelashes stand out well on the face, and nails are partially formed, covering only part of the nail plate. 
If we consider the baby with the help of modern ultrasound technology, you can see how he frowns, blurs into a fleeting smile and grimaces. The child already holds the neck and is able to turn the head, and the ears and eyes are getting closer to the right place.
Seventeenth week (113-119 days)
seventeenth week of pregnancy begins with a fetal weight of 120-150 g and a body length of 14-15 cm. The baby's skin is still thin, but fatty tissue is intensively formed under it. Milk teeth continue to improve, starting to become covered with dentin.
The reaction to sound stimuli becomes more pronounced, and many experts say that from the beginning of the 17th week, the fetus begins to hear (sharp sounds make it increase activity). 
Also fetal position changes: the head rises and occupies an almost vertical position, the arms are bent at the elbow, and the fingers are clenched into a fist. The child's immune system is activated, as a result of which interferon and immunoglobulin are produced in the body. This allows the little man to protect himself from infections of the mother.
At the same time completes its development and a small heart, intensively pumping blood. There is an opinion about the criticality of the 17th week for the mental development of the baby, therefore, both the mother and the father need to turn to him more often, speaking affectionately.
Eighteenth week (120-126 days)
At this time, we can say that the second trimester is approaching the middle. The fetus reached 20 cm in length (from the coccyx to the crown) and gained up to 200 g of weight. His limbs (both upper and lower) are already fully formed, they have phalanges of fingers and even prints.
They continue their development brain and immune system, hearing improves, and a pronounced reaction to light appears. The fatty layer is actively formed and even the rudiments of molars are laid.
If this is not the first pregnancy for a woman, then with a high degree of probability she Feel the first movements of your baby. The norm is about 10 light shocks per day.
Nineteenth week (127-133 days)
At that time we can talk about a significant jump in the development of the fetus. Movements are more orderly, the respiratory system improves, and the body is covered with primordial lubrication. The weight of the baby reaches 250-300 g, and the length of the fetus fluctuates around 22-23 cm.
At the same time, the dimensions of the head for the first time begin to lag behind the indicators of the trunk and limbs, which are actively lengthening.
The pituitary gland, sex glands, adrenal glands, pancreas, thyroid and parathyroid glands work intensively. The composition of the blood also changes greatly, in addition to leukocytes and erythrocytes, lymphocytes and monocytes also appear in it.
On the this period the baby's tremors are felt not only by the expectant mother, but also by the father, if he puts his hand on his stomach.
Twentieth week (134-140 days)
The length of the baby's body increases to 25 cm, and the mass is already about 340 g. The skin remains the same thin and covered with downy hairs, often remaining until birth.
However, fatty subcutaneous tissue begins to develop more intensively. 
Also at 20 weeks intrauterine development, the baby has a blinking reflex, coordination of movements improves and facial expressions become more pronounced.
Having a regular stethoscope available, you can safely listen to the rhythm of his heart, which becomes more stable.
Twenty-first week (141-147 days)
When the fetus reaches 21 weeks of its intrauterine development, its growth is measured already from the heels, and not from the coccyx, as it was before. Now it is approximately 26.7 cm, with a baby weighing about 360-380 g.
Every day subcutaneous adipose tissue is getting bigger, the fetus even has wrinkles on the body. The digestive system begins to work more actively and the fetus swallows amniotic fluid all the time. 
Bone and muscle tissue continue to strengthen, and the spleen also joins the actively working endocrine glands.
Despite its considerable growth, the baby still feels free in the womb of the mother and can occupy almost any position.
Twenty-second week (148-154 days)
Little man size at this time it increases to 28 cm, and the weight will be in the range of 450-500 g. The head becomes proportional to the body and limbs, and the legs are almost constantly in a bent position.
The spine of a child is characterized by the presence of all ligaments and joints, but the bones continue to strengthen further. 
An active development of the nervous system is observed: the baby begins to be interested in his face, legs and arms, he brings his fingers to his mouth with interest and tilts his head.
Heart significantly increases in size because the cardiovascular system is still improving.
Important! If, for any reason, the pregnancy is terminated at 22 weeks, modern medical technology allows such a child to come out, since he is considered completely viable.
Twenty-third week (148-154 days)
In addition to the further development of all main systems and organs a small person, who, by the way, weighs 500 g at 23 weeks and has a height of 28 to 30 cm, a pigment begins to be synthesized in the skin, giving the skin a bright red color.
Due to the thin subcutaneous fat layer, the fetus seems very thin and very wrinkled, and the lubrication is mainly concentrated in the folds of the body. 
The frequency of respiratory movements increases and now equals 50-60 times per 1 minute and the swallowing reflex is still well developed, as a result of which the child swallows part of the amniotic fluid.
Interesting that even such a crumb can have hiccups, which a woman feels as rhythmic movements for a couple of minutes.
Moreover, some scholars believe that from that time, baby is able to dream, because it was possible to fix the phase of REM sleep in the fetus.
Twenty-fourth week (162-168 days)
Asymmetric until recently, the fetus is increasingly becomes like a child. There is still a little adipose tissue, so the weight gain is not too noticeable and the baby weighs 600 g (height is about 32 cm).
It should also be noted that it is at week 24 that a small organism begins to independently produce growth hormone, which allows it to grow faster in the future.
The fetus has already taken almost all the space in the uterine cavity, but so far it can roll over. 
By the end of the sixth month the sense organs are well developed and vision begins to develop (when the abdomen is illuminated with bright light, the baby immediately squints strongly and turns away).
Completes its development respiratory system, the bronchial tree and lungs are already fully formed, covered with a special substance - a suffracant (prevents drying and closing of the capillary sacs when inhaling air after birth).
Sweat and sebaceous glands also differ in more streamlined work than in previous stages of development, but the main thing for the mother is that at this particular time between her and the unborn baby an emotional connection is formed: fear, anxiety, melancholy and other negative emotions cause similar feelings in the child.
Twenty-fifth week (169-175 days)
The child grows up to 30-34 cm and weighs already 650-700 g. The skin becomes more elastic, there are fewer folds, but it still remains thin and has a large number of capillaries that color it reddish.
The front part is even more formed and the eyes, eyelids, eyelashes, eyebrows, lips, cheeks and auricles already stand out well on it.
There is a rapid development of the bone marrow - now the main component in hematopoiesis.
Also observed important processes in the formation of the lungs: alveoli appear, which are in a "deflated" state (without air) before birth, and from the reproductive system, the formation of the testicles (in boys) or the vagina (in girls) is noticeable.
Twenty-sixth week (176-182 days)
The growth of a little man at this stage of his development is approximately 36 cm, with a weight of about 750-760 g. Continues to increase muscle mass and fat layer, bones are strengthened and permanent teeth develop further. 
In general, the child has already acquired all his personality traits: eyelashes and eyebrows have taken their places, the ears have taken shape and now they protrude a little from the head.
The lungs take their final shape and take their proper place, that is, the child is now completely ready. breathe on your own after its birth. Also, the eyes begin to open, the fetus already recognizes the voices of the parents.
The last stage of pregnancy, which means that soon you will meet your baby and take him in your arms.
You have already learned how the child grows in the previous 26 weeks, that by this time all the main systems and organs have formed, but the process of its full development during pregnancy has not yet been completed, there are many interesting things ahead of you. 
Twenty-seventh week (183-189 days)
At this time the next phase of active growth of a small life begins. The weight of the baby is already 850 g with a body length of 37 cm.
All organs of the endocrine and other systems (including the pancreas and thyroid glands, as well as the pituitary gland) function well, and the fetus itself is very active (but can still be freely placed in the uterine cavity). 
At the same time begins to develop its own metabolism. The skin becomes brighter, and under it the muscle tissue increases more and more.
Twenty-eighth week (190-196 days)
The weight of the baby has reached 950 g, and the length is 38 cm. Adipose tissue continues to accumulate, vellus hair begins to fall out (remain only on the back and shoulders). Eyebrows, hair on the head and eyelashes acquire a darker color. 
The baby opens his eyes much more often, but the cartilages of the ears and nose remain the same soft, the nails do not reach the edge of the phalanx of the fingers.
noteworthy that it is at this time that one hemisphere of the brain begins to work more actively: if the right one, the child will be left-handed, and if the left one, right-handed.
Twenty-ninth week (197-203 days)
The child is getting ready to go out Big world : the immune system copes with its functions quite well, and the body's thermoregulation improves its work. The weight of the baby is now about 1200 g, and the height reaches 39 cm.
Such dimensions significantly reduce the free space in the uterus and all fetal movements are expressed in infrequent pushes with arms and legs. 
The organs and systems of a small organism continue to improve, for example, up to 500 g of urine is excreted daily by the kidneys.
With the beginning of the 29th week, the amount of original lubrication begins to decrease, the skin brightens and straightens more and more.
Thirtieth week (204-210 days)
The weight of the child continues to grow and reaches 1300-1350 g, although the length of the body remains approximately the same - 38-39 cm. Fatty tissue continues its increased accumulation, which more and more straightens the folds on the skin.
The lack of space in the mother's womb causes the baby to take a certain position: curl up and cross his legs and arms. 
Also continue develop alveoli, surfactant is actively produced, that is, the child is preparing for the start of spontaneous breathing.
The development of the brain is characterized by the appearance of a large number of convolutions and an increase in the area of the cortex.
Nerve cells function, fibers form, around which a myelin protective sheath appears.
Baby's liver stores iron, thanks to which the baby will supply blood cells for the entire first year of his life.
Thirty-first week (211-217 days)
In a baby who by this time already weighs 1500-1700 g and has a height of 40 cm, it is significantly changes in sleep and wake patterns.
Motor activity is reduced, although during wakefulness the child kicks well. In addition, these processes are accompanied by the closing or opening of fully formed eyes.
Did you know? At birth, the iris of all children has the same blue color and only after some time begins to change.
The volume of the brain during this period is 25% of the volume of this organ in an adult.
A connection is established between the nerve cells, and the nerve fibers continue to "grow" with protective sheaths. Further formation of all organs and systems continues.
Thirty-second week (218-224 days)
If at the previous stages the child has not yet turned upside down, then this usually happens at this time.
Now the baby weighs about 1800 g with a height of 42 cm, and therefore there is less and less space for him. Active accumulation of fatty tissue smoothing the skin.
The internal organs are still improving: the endocrine system secretes hormones, and the lungs accumulate surfactant. In addition, the child begins to produce a special hormone that promotes the appearance of estrogen in the mother's body, which activates the process of producing milk for feeding.
On the head, the baby's hair becomes thicker, but still retains softness.
Thirty-third week (225-231 days)
The lungs are fully formed and in the case of early birth at this time, the child will be able to breathe without outside help. He weighs about 2 kg and has reached a height of 43-44 cm.
All parts of the body become more proportional to each other, and systems and organs continue to improve (for example, the mass of the heart increases and the tone of the blood vessels increases). The position of the baby's body is fixed in the uterus (he can turn his head or booty down), usually after that he will no longer roll over.
Thirty-fourth week (232-238 days)
The body weight of the baby has already reached 2-2.5 kg, and the length of the body is at the level of 44-45 cm. Despite the fact that it is practically no different from a newborn, the body is still improving all its parts.
cranial bones remain the same soft and mobile, which is necessary for the smooth passage of the birth canal at birth. Increased hair growth begins on the head and they can even change color. 
Also worth noting intense bone strengthening, for which the fetus is forced to take calcium from the mother's body. Constant swallowing of amniotic fluid by a child stimulates the functioning of the kidneys and gastrointestinal tract.
Thirty-fifth week (239-245 days)
The baby adds 25-35 g daily, because of which the weight can vary significantly and at the end of the week it will be 2200-2700 g (with a height of 46 cm). All internal organs continue to develop, and fatty tissue still accumulates, thanks to which the child becomes well-fed.
In the intestines of the fetus there is already a sufficiently large amount meconium, which usually departs 6-7 hours after birth. The crumbs are actively trained to suck on the mother's breast - he sucks his fingers (even on his feet) and swallows amniotic fluid.
Thirty-sixth week (246-252 days)
Weight and height an already almost fully formed child is now very different and can be from 2 to 3 kg and from 46 to 48 cm. The adipose tissue is already quite well developed, the skin color acquires a light shade, and wrinkles and folds completely disappear.
Unlike other bones, cranial bones remain as soft and have so-called movable "fontanels". All organs and systems are completely ready for your work in the big world.
Thirty-seventh week (254-259 days)
The fruit reaches 48-49 cm in length, and its weight is within 3 kg, with a slight deviation from this value. The skin is already well lightened and thickened, and the fat layer increases daily by 14-15 g per day. 
The cartilages of the auricles and nose become more dense and elastic, maturation ends lungs and digestive system. From this moment, even if childbirth begins, they will no longer be considered premature.
Thirty-eighth week (260-266 days)
It is likely that at this time your baby will come to light, but even if this does not happen, then it's okay if he grows up a little more in the womb.
No special processes at 38 weeks already not happening, baby only gaining weight. All his organs and systems have already fully developed and are fully functioning.
Thirty-ninth week (267-273 days)
Normally, two weeks before the expected date of birth, baby starts to fall, more and more clinging to the bones of the pelvis. It has already fully matured and the placenta begins to gradually age, as a result of which all metabolic processes in it significantly worsen. 
Your baby's weight is increasing day by day. by 30-35 g per day, which is accompanied by a complete change in the proportions of his body: the shoulder girdle and chest are already well developed, the tummy is rounded and the limbs have become longer.
Continues development of the central nervous system of the child, although this process will continue after its birth. Amniotic fluid during this period is updated every 3 hours, although their total amount is significantly reduced.
Fortieth week (274-280 days)
The fortieth week is considered last stage of pregnancy, but in fact, the child may appear both earlier and later than the due date. 
At that time all indicators of its development are fully consistent with the characteristics of a newborn baby. Body weight ranges from 2.5 to 4 kg or even higher, and the average height is 49-52 cm.
Intermittent contractions of the uterus are observed, which the woman feels as episodic drawing pains in the lower part. The bones of the child's skull are still soft and pliable. 
Through all stages of its development, a little man appears in front of you, very similar to his parents, but how he grows up depends only on you.
During the period of bearing a child, a woman is constantly observed by a doctor.
This allows you to avoid unpleasant consequences and come to a safe delivery. Despite the control of doctors, the expectant mother wants to know what is happening inside her body, how the fetus develops through the weeks of pregnancy, what sensations should arise and what the baby himself experiences. The gynecologist does not always have enough time to answer all the questions of interest, so the pregnant woman turns to the Internet.
Fetal development in the first trimester
The first trimester lasts approximately from conception until the 12th week of pregnancy. This period is considered the most crucial, since at this time the laying of organs takes place. There is no placenta in the full sense of the word yet, so a woman needs to be careful in using drugs, as they enter the embryo through the blood (up to 9 weeks, the concept of “embryo” is accepted, then “fetus”) and can cause irreparable harm to it.
The first 2 weeks after conception, the embryo is attached to the uterus. At this time, a woman may not notice changes at all, no weight gain occurs. Starting from the 3rd week of pregnancy, the embryo begins to actively grow and develop.
The development of the fetus occurs rapidly and largely depends on the state of the mother's body.
3 weeks. The size of the fetus at this time is not more than 2 mm. Already now the formation of the neural tube, chord begins, blood vessels are laid.
4 weeks. The size of the embryo doubles, it is already about 4 mm. It has germ layers that will continue to develop, transforming into full-fledged tissues.
5 weeks. At this time, the woman begins to suspect that she is pregnant. Her unborn child reaches 12 mm in length and weighs about 2 g. The laying of the brain and other internal organs occurs. There is no placenta yet, it is replaced by the chorion, a membrane covered with villi, which will then grow into vessels, capillaries and become the placenta.
6 weeks. The brain develops more intensively than other organs, so the head is still much larger than the body. Sexual organs are formed, but it is not yet possible to determine the sex. The nervous system is improving, facial features are beginning to be determined.
7 weeks. By the beginning of the 7th week, the length of the fetus is already almost 2 cm. The urinary system is being formed in it, the fingers are separated on the hands and feet. On ultrasound, you can determine the heartbeat, which normally is no more than 160 beats per minute.
8-9 weeks. The embryo turns into a fetus, fat cells appear in it, a four-chambered heart is formed, the kidneys begin to work, releasing the first urinary fluid.
10-12 weeks. By the end of the first trimester, the fetus already has facial expressions, can actively move, breathe, swallowing amniotic water. The reproductive organs are in their infancy.
At the end of the first trimester, a woman is scheduled for screening and ultrasound. These procedures allow you to identify the pathology of the development of pregnancy, if any. Gender at this time can be determined, but the probability of error is high.
Second trimester of pregnancy
The second trimester lasts until 28 weeks. At this time, the fetus is actively increasing in size, and the woman's belly is noticeably rounded. If there was a threat of miscarriage at the beginning of pregnancy, the risks usually decrease by the second trimester. Toxicosis at this time also weakens.
The description of the development of the fetus at this time is of particular interest to expectant mothers, because they begin to feel the first movements of the child. If before the movements were imperceptible, now tremors can be noticed.
Every week the fetus becomes larger, its internal organs are improved:
13-15 weeks. During this period, the fetus acquires its own red blood cells, which begin to circulate in the blood. The digestive system continues to form, and the baby is already making the first swallowing movements. The sucking reflex is activated, so on an ultrasound, the doctor may notice that the child is sucking his thumb. The movements of the fetus become more active, it can roll over.
16-18 weeks. By the end of the 18th week, the genitals are fully formed. The fetus not only moves itself, but also turns its head. He starts to blink, facial expressions improve. The immune system is also formed, but before birth, the protective functions of the child will be completely dependent on the mother.
19-20 weeks. The growth of the fetus at this stage is already more than 25 cm. The cerebral cortex is being laid, therefore, during this period, toxic effects (substances, nicotine, alcohol) significantly increase the risk of developing mental retardation in a child.
21-23 weeks. Starting at 22 weeks, the fetus can survive outside the woman's body. The lungs are already formed enough to breathe on their own. However, a child born at such a time will have many health problems.
24-26 weeks. The fetus is actively gaining weight. For this reason, the heart contracts more often, so they talk about the physiological arrhythmia of the fetus.
27-28 weeks. By week 28, the centers of vision and hearing are formed. At birth at this time, the baby begins to hear and see what is happening quite quickly.
You can learn from an obstetrician-gynecologist about how the fetus should develop by weeks of pregnancy, a description of its appearance and feelings of a woman. The second trimester is considered relatively calm for mom. Various pathologies, including intrauterine death, are rare at this stage of pregnancy. Nevertheless, a woman is assigned a series of tests to determine the development of the fetus and the condition of the expectant mother.
Baby in the third trimester of pregnancy
The final third trimester is full of worries for a woman. She prepares for childbirth, prepares the house for the arrival of the child. And the baby is about to be born.
It is believed that childbirth occurs at the 40th week of pregnancy, but even if a woman walks, up to 42 weeks this is considered the norm.
The child is becoming more and more like a newborn, its development is quite rapid:
29-30 weeks. The child has already formed taste buds, so he begins to respond to the mother's food. The taste of amniotic fluid depends on the foods eaten, which can cause the approval or discontent of the baby. Milk teeth are formed inside the gums. Mature tear ducts allow the child to cry. By the end of the 30th week, the baby should assume a position that will allow him to be born, that is, he turns his head down.
31-33 weeks. The formation of organs at this time is completely completed. The child's eyes begin to react to light, nails appear, the skin acquires a pinkish tint. The development of the child's immune system continues.
34-36 weeks. Basically, at this stage, the child accumulates subcutaneous fat, gaining mass. He has cheeks. The movements become less active, as the child becomes cramped in the mother's stomach, but he actively kicks, the mother begins to distinguish between kicks and hand strikes.
36-37 weeks. The baby already looks completely like a newborn and is ready to be born, but the heart valve has not yet closed. Weight at this time usually reaches 3 kg. The placenta begins to gradually age, which is considered the norm.
39-40 weeks. There are only a few days left before the birth. All organs and systems are formed, the lungs are already fully prepared for breathing.
If the pregnancy is terminated at this time, the development of the fetus allows it to survive outside the mother's body. The chances of survival even at the beginning of the third trimester are very high.
By the time of delivery, the child should weigh 2500-4000 g. If the fetus is large enough, the question of planned caesarean section. Despite the fact that premature birth in the 3rd trimester is no longer so dangerous for the baby, there is still a risk of fetal death, neurological problems, so doctors will try to stop tribal activity up to 36-37 weeks.
Feelings of a woman as the fetus develops
During pregnancy, a new organism grows and develops inside the body of a woman for 9 months. This cannot but affect her feelings. If the pregnancy is the first, many sensations are not yet familiar to the woman and can cause fear. All doubts and suspicions should be reported to the doctor.
The closer to childbirth, the more new emotions and physical sensations the expectant mother experiences.
Depending on how the pregnancy progresses week by week, the development of the fetus and sensations will be constantly updated.
Since a trimester lasts 12-15 weeks, the sensations during one trimester can constantly change, so it's better to talk about what a woman experiences each month of pregnancy:
1 month. At this time, the woman only finds out that she is pregnant or remains in the dark for a while. Signs of this condition may be absent altogether, however, some pregnant women note swelling and soreness of the breast, mild nausea, and pulling pains in the lower abdomen.
2 month. In the second month, a woman usually already knows that she is pregnant. Most pregnant women at this stage begin severe toxicosis, nausea, vomiting, and food preferences change. Also, due to hormonal changes, a woman becomes sleepy, gets tired quickly.
3 month. Feelings from 2 months are not much different. Toxicosis can continue, the breast continues to grow and swell. The nipples become darker in color.
4 month. At the 4th month, a small tummy begins to appear. The muscles of the abdomen and back may ache a little due to the sprain. Also at this stage, a woman is faced with such an unpleasant problem as constipation.
5 month. At the 5th month, a woman feels the movements of her child. Since the uterus grows rapidly and presses on the internal organs, heartburn may occur. The skin of the abdomen and thighs is stretched, so it starts to itch.
6 month. The stomach grows rapidly, the back begins to get tired. The first stretch marks may appear, so it is recommended to wear a bandage.
7 month. A woman begins to visit the toilet more often, her back muscles hurt more. There is insomnia. The movements of the child are so strong that they can cause discomfort to the mother.
8 month. Due to the weight gained, the woman quickly gets tired, it is difficult for her to move. Sweating increases. changing psychological condition, the pregnant woman becomes more capricious, anxiety conditions are possible.
9 month. The body prepares for childbirth, so the stool becomes more liquid and frequent, the intestines are emptied, the woman loses a little weight. The abdomen drops, so the urge to urinate becomes even more frequent.
Some pain during pregnancy is normal, as the woman's body is being rebuilt, but if the pain is too strong, this should be reported to the doctor immediately.
Possible deviations
Of course, a woman during pregnancy is not recommended to think about the bad. Stress and pessimism are bad companions of pregnancy. However, not everyone manages to remain in a state of calm. If there has already been an unsuccessful pregnancy in the anamnesis, then the woman will try to find out as much as possible about what can go wrong.
Depending on how the pregnancy proceeds, the development of the fetus and the feelings of the woman also gradually change. However, not all deviations can be noticed without examination, so all tests and ultrasound should be done on time on the recommendation of a doctor.
The most common fetal malformations are:
Down Syndrome. Despite the fact that older mothers fall into the risk group, no one is immune from this pathology. This is a mutation that is associated with the appearance of an extra chromosome. It leads to dementia and growth retardation of the child. During the first screening at week 12, it becomes clear whether there is a chance of a baby with Down syndrome.
Patau syndrome. Severe chromosomal disease, which is also associated with gene mutation. The child has a violation of mental development, deafness and many other pathologies are possible. As a rule, children with Patau syndrome rarely live past a year.
Heart defects. Heart disease in a child can also be determined at the stage of pregnancy. This pathology is very diverse. You can live with some vices all your life, while others are so severe that they are inoperable and incompatible with life.
Defects or absence of internal organs, body parts. It is difficult to determine the causes of this pathology, but it is acquired and is not associated with genetics. Failure occurs at the stage of laying organs. Most often, the brain and limbs are affected.
It is worth remembering that most pathologies and abnormalities in the development of the fetus can be avoided. To do this, it is recommended that both parents be examined before conception, as well as be observed by a doctor and follow his recommendations.