How long does it take for a fetus to be born? Intrauterine development and child growth by week

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

Photo of embryo development by day after IVF

Stages of embryo development

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

First trimester

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

Second trimester

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

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

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

Third trimester

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

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

Human fetal development

Fruit size chart

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

The appearance of a child in the family- a desired and very exciting moment for which young parents begin to prepare as soon as they learn about pregnancy. Therefore, information regarding fetal development by month of pregnancy is always very important and informative. In addition, the birth of a new life and the development of a little person will also be interesting to people who are not yet thinking about procreation, since nature provides for a simply unique process. It consists of three stages: first, second and third trimesters, during which the formation of the child occurs.

First months of pregnancy- the most important for the further development of the fetus, since right now the fertilized egg attaches to the wall of the uterus and slowly begins to turn into a child.

Whether it will take hold or not, and how correctly the further formation of all the little person’s systems will proceed, depends on a number of factors. Let's try to understand the features of this process week by week.

First week (days 1-7)

We can talk about the beginning of pregnancy when fertilization of a female egg by a male cell (sperm) occurs; they talk about this in biology lessons 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 within a couple of hours after the “meeting,” the fertilized egg quickly begins to divide, and then descends through the fallopian tube into the uterine cavity. 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 seventh day it penetrates the uterine wall, and the villi of its cells (external) connect with 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 attaches to the wall of the uterus (implantation), a woman may experience bleeding from the vagina, but this is a completely normal phenomenon and there is no need to worry.

Second week (8-14 days)

The cells of the embryo continue to grow into the mucous membrane of the uterus, 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 a complete absence any heavy bleeding, because their presence indicates the possible presence of a disease, for example, endometrial hyperplasia or impaired ovarian function, 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 one, but for now 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 begin to form, the respiratory, circulatory, nervous, digestive and excretory systems are 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 is the beginning of the embryo's heartbeat. Now we can say with confidence that conception has occurred, although the possibility of miscarriage cannot be ruled out.

Did you know? In the third week of pregnancy, the body weight of the unborn baby is only 2-3 mcg, and the length of the “little body” is from 0.15 to 0.2 mm.

Fourth week (22-28 days)

The laying and formation of fetal organs continues, from which the intestines, liver and lungs can be distinguished. The performance of the still tiny heart is increasing more and more.

At the end of the first month During pregnancy, folds of the body are formed in the embryo, and a spine (notochord) is formed, dividing the embryo into two halves with a clear separation of the limbs. On the head of the unborn baby, pits begin to form, which will later 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 to the coccyx varies between 1.5-2.5 mm), all organs of the digestive (pancreas and liver), respiratory (lungs, larynx, trachea), genital (formation of the precursors of the reproductive organs) begin to take shape cells), nervous (formation of parts of the brain) systems, and also the further development of sensory organs - the eyes and inner ear.

Besides, in the fifth week The umbilical cord is already noticeable and the baby’s limbs continue to form, and the rudiments of marigolds are formed on them. On the front part the nasal cavity and upper lip are already visible.

Many women at this stage clearly feel pregnancy, because the uterus sharply enlarges (outwardly this is not noticeable at all) and puts pressure on the bladder. appear first signs of toxicosis and increased sensitivity to various odors.

Sixth week (36-42 days)

By the sixth week, the unborn baby 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 being formed, which is just beginning to perform its direct functions, and blood circulation with the embryo has not yet been established.

Continue actively form all parts of the brain, and if you make an encephalogram, you can record the signals sent by the tiny brain. The formation of facial muscles also begins, the eyes of the embryo become more pronounced and are not covered by eyelids.

Upper limbs lengthen slightly, 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 embryo body is approximately 10-13 mm. The placenta becomes much thicker, and the baby and mother are already firmly connected by the umbilical cord, through which the uteroplacental circulation is finally formed.

It is noteworthy that the little man still there is a tail, 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. The shoulders and forearms are clearly visible.

Fetal eyes covered with eyelids that protect them from drying out, and the child sometimes opens his mouth slightly. The nose and nasal fold are formed, two paired elevations appear on the sides of the head: from them the auricles then develop.

It was at this time a mucus plug forms, which will close the cervix and protect the baby from harmful environmental factors.

Eighth week (50-56 days)

The baby's body gradually straightens and its length (measured from the tailbone to the crown) corresponds to 20-21 mm (by the end of the week). Continue their formation basic body systems: digestive, cardiovascular, respiratory (especially lungs), urinary and reproductive (in boys, testicles begin to develop).

The 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 ears are formed, and the process of lip formation is completed.

And the head and all the limbs begin grow rapidly, ossification of the long bones of the legs and arms also occurs. On an ultrasound, you can notice small fingers with no membranes between them. The eighth week is the period of formation of the optic nerve.

The embryo begins to move, but due to its small size, the woman does not feel these movements in any way.

Important! It is in the eighth week that the embryonic stage comes to an end and the embryo is already called a fetus.

Ninth week (57-63 days)

The length of the fruit is in the range of 22-31 mm. The blood vessels of the placenta continue to improve, the system of bones and muscles intensively develops, in particular, the joints of the legs and arms are formed.

Peculiar changes are also noted in the functioning of the cardiovascular system: the heart is already capable of making 150 beats (in 1 minute) and pumping blood through the blood vessels. The brain is still actively growing and developing, the structure of the cerebellum is emerging, and the pituitary gland is being formed.

Also The adrenal glands begin to actively develop, while producing hormones important for the body, lymph nodes develop. At the same time, cranial, spinal and intervertebral nerves appear.

In the unborn child The cartilage tissue also improves, which at this stage is expressed in the design of the auricles, the cartilage of the larynx and the formation of the vocal cords.

At nine weeks the fetus looks like a small pea pod, which through the umbilical cord removes its waste products into the mother’s body.

Tenth week (64-70 days)

The fruit (from crown to tailbone) has already reached a length of 35-40 mm. The most interesting change is the disappearance of the ponytail and the formation of the buttocks, but this, of course, is not the only important change.

Further, the nervous system (already divided into central and peripheral) of the fetus is improved, which can now perform not only chaotic movements, but also shudder in response to a stimulus (the first reflexes are formed).

Eg If the baby accidentally touches the wall of the uterus, he may turn his head, bend or straighten his arms and legs, or even be pushed to the side. At the same time, the development of the diaphragm is coming to an end, which as a result will be directly involved in the breathing process.

With high speed the brain is formed and in one minute up to 250 thousand neurons can be created in it.

Eleventh week (71-77 days)

The body of the unborn child at this time still remains disproportionate: the large head stands out strongly against the background of the small body, and the arms are longer than the legs, bent at all joints and located in a tucked state. By the end of the eleventh week, a fetus measuring 4-5 cm is in the woman’s womb.

At this time, the placenta already fully performs all the functions assigned to it and provides the little person with a sufficient amount of oxygen and micronutrients. In addition, it is she who pushes metabolic products and carbon dioxide out.
The further formation of the baby’s eyes is also noticeable, because the iris appears, which will ultimately determine his eye color.

Appear in the fetal blood first lymphocytes, directly involved in the formation of immunity.

Did you know? At this stage of intrauterine development, the unborn child's liver makes up 10% of his entire body. The intestines also make their first movements (something like peristalsis).

According to experts, at the 11th week the formation of the little person’s sense of smell also occurs.

Twelfth week (78-84 days)

Fruit size(from the crown to the coccyx) approximately within 50-60 mm, its genital organs (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 arrangement (exactly like in an adult).

The child is already can swallow amniotic fluid, clench and unclench your fingers, as well as grab your thumb with your mouth and actively suck it. In addition to red blood cells, leukocytes (white blood cells) also appear in the baby’s blood, and single respiratory movements can also be recorded.

Of course, before the moment of birth, the fetus is not yet able to breathe on its own and its lungs do not function properly, but it is quite capable of performing rhythmic movements chest.

Did you know? Starting from the 12th week, unique patterns - fingerprints - are formed on the pads of the tiny person's fingers.

Thirteenth week (85-91 days)

Future baby size reaches approximately 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 week by week.
In addition, week 13 is also significant as the beginning formation of baby teeth, which are located under the lower and upper jaws.

By the way, there are crumbs in the intestines the first villi appear, which after birth will begin to take a direct part in the process of digestion and promotion of food. The pancreas produces the first insulin, and the vocal apparatus is also actively forming.

The baby’s emotional sphere also develops, which 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 fetal body becomes longer and is already 8-9 cm, and its proportions take on an increasingly familiar appearance. The first hairs are already visible on the head, although they are still quite thin and do not have a specific color.

The surface of the body is covered with sparse vellus 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 that mixes with the amniotic fluid, is completed.
Swallowing amniotic fluid, a child can determine its taste by reacting to sweets with rapid swallowing reflexes or weak sips to bitter ones.

My work begins cells of the pancreas and pituitary gland. In boys, the prostate gland actively develops, and the ovaries of girls are located in the pelvic region.

If you do an ultrasound on quality equipment, then with a high degree of probability it will be possible to find out the gender of your baby.

If we look at the stages of pregnancy in detail by week, then starting from the fifteenth we can talk about the second trimester of pregnancy. Before this time, the fetus has already strengthened in the uterus, all its main systems and organs are almost formed, which reduces the risk of unforeseen situations.
However, quite Expectant mothers should not relax, since there are still many important stages of the baby’s development ahead.

Fifteenth week (99-105 days)

With the beginning second trimester, the fetus weighs approximately 70-75 g, and its length (still measured from the crown to the tailbone) is 10 cm. Despite the fact that the child’s head is large, 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 excrete original feces (meconium).

However, the most important process in 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 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 are clearly visible 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 technologies, you can see how he frowns, breaks into a fleeting smile and makes grimaces. The child is already holding his neck and is able to turn his head, and his ears and eyes are getting closer and closer to their proper place.

Seventeenth week (days 113-119)

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 as thin, but fatty tissue is intensively formed under it. Baby teeth continue to develop and begin to become covered with dentin.

The reaction to sound stimuli becomes more pronounced and many experts claim that from the beginning of the 17th week the fetus begins to hear (sharp sounds force it to increase activity).
Also the location of the fetus changes: the head rises and takes 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 the mother's infections.

At the same time The small heart, vigorously pumping blood, also completes its development. There is also an opinion that the 17th week is critical for the mental development of the baby, therefore both mother and father need to contact him more often, talking affectionately.

Eighteenth week (120-126 days)

At this stage, we can say that the second trimester is approaching the middle. The fruit 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.

Continue their development brain and immune system, hearing improves, and a pronounced reaction to light appears. The fat 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 will feel the first movements of his baby. The norm is approximately 10 light tremors per day.

Nineteenth week (127-133 days)

At that time we can talk about a significant leap in fetal development. Movements are more orderly, the respiratory system is improved, and the body is covered with vernix lubrication. The baby's weight reaches 250-300 g, and the length of the fetus varies around 22-23 cm.

At the same time, the size of the head for the first time begins to lag behind the indicators of the torso and limbs, which are actively lengthening.

The pituitary gland, gonads, 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 this term The baby's kicks are felt not only by the expectant mother, but also by the father if he places his hand on his stomach.

Twentieth week (134-140 days)

The length of the baby's body increases to 25 cm, and the weight is already about 340 g. The skin remains the same thin and covered with vellus hairs, often remaining until birth.

However, subcutaneous fat begins to develop more intensively.
Also at 20 weeks During intrauterine development, the baby develops a blinking reflex, coordination of movements improves and facial expressions become more pronounced.

Having a regular stethoscope, you can calmly listen to the rhythm of his heart, which becomes more stable.

Twenty-first week (days 141-147)

When the fetus reaches 21 weeks of intrauterine development, its growth is measured from the heels, and not from the tailbone, as was previously the case. Now it is approximately 26.7 cm, with the baby weighing about 360-380 g.

Every day subcutaneous adipose tissue is getting bigger, the fetus even develops folds on its body. The digestive system begins to work more actively and the fetus constantly swallows amniotic fluid.

Bone and muscle tissue continue to strengthen, and the spleen also joins the actively working endocrine glands.

Despite his considerable growth, the baby still feels free in the womb of his mother and can occupy almost any position.

Twenty-second week (148-154 days)

Little man size at this stage 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 child’s spine is characterized by the presence of all ligaments and joints, but the bones continue to strengthen.
The 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.

The heart is significant increases in size, since the cardiovascular system is still being improved.

Important! If for some reason the pregnancy is terminated at 22 weeks, modern medical technologies allow such a child to be born, since it is considered fully viable.

Twenty-third week (148-154 days)

In addition to further development of all main systems and organs a small person, who, by the way, at 23 weeks weighs 500 g and has a height of 28 to 30 cm, pigment begins to be synthesized in the skin, giving the skin a bright red color.

Due to the thin subcutaneous fat layer, the fetus appears very thin and strongly wrinkled, and lubricant is mainly concentrated in the folds of the body.
The frequency of respiratory movements increases and is now equal to 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 baby can have hiccups, which a woman feels as rhythmic movements for a couple of minutes.

Moreover, some scientists believe that from this time on, baby can dream, since it was possible to record REM sleep phases in the fetus.

Twenty-fourth week (162-168 days)

The fruit, which was asymmetrical until recently, 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 approximately 32 cm).

It should also be noted that it is at week 24 that the small body begins to independently produce growth hormone, allowing it to grow faster in the future.

The fetus has already taken up almost all the space in the uterine cavity, but can still turn over.
By the end of the sixth month The sense organs have developed well and vision begins to develop (when the abdomen is illuminated with bright light, the baby immediately squints his eyes tightly and turns away).

Completes its development and respiratory system, the bronchial tree and lungs are already fully formed, coated with a special substance - suffracant (prevents the capillary sacs from drying out and closing when inhaling air after birth).

Sweaty and greasy glands are also distinguished by more streamlined work than at previous stages of development, but the main thing for the mother is that it is at this time between her and the future baby an emotional connection is formed: fear, anxiety, melancholy and other negative emotions cause similar feelings in a child.

Twenty-fifth week (169-175 days)

The child grows to 30-34 cm and already weighs 650-700 g. The skin becomes more elastic, there are fewer folds, but it still remains thin and has a large number of capillaries, coloring it reddish.

The front part is even more shaped and the eyes, eyelids, eyelashes, eyebrows, lips, cheeks and ears are already clearly visible.

There is a rapid development of bone marrow - now the main component in hematopoiesis.

Also observed important processes during lung formation: alveoli appear, which before birth are in a “deflated” state (without air), and from the side of the reproductive system, the appearance of the testicles (in boys) or vagina (in girls) is noticeable.

Twenty-sixth week (176-182 days)

The height of the 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, ears have taken shape and now they protrude slightly 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 his birth. The eyes also begin to open, the fetus already recognizes the voices of its parents.

The last stage of pregnancy, which means that you will soon meet your baby and hold him in your arms.

You have already learned how a child grows in the previous 26 weeks, that by this time all the main systems and organs are formed, but the process of its full development during pregnancy is not yet completed, a lot of interesting things await you.

Twenty-seventh week (183-189 days)

At this time The next phase of active growth of a small life begins. The baby's weight 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) are functioning well, and the fetus itself is very active (but can still move freely into the uterine cavity).

At the same time its own metabolism begins to develop. The skin becomes lighter, and underneath it the muscle tissue increases more and more.

Twenty-eighth week (190-196 days)

The baby's weight has reached 950 g, and his length is 38 cm. Fatty tissue continues to accumulate, vellus hair begins to fall out (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 just as soft, and the nails do not reach the edge of the phalanx of the fingers.

Remarkable that it is at this time that one hemisphere of the brain begins to work more actively: if the right hemisphere, the child will be left-handed, and if the left hemisphere will be right-handed.

Twenty-ninth week (197-203 days)

The child is increasingly preparing to enter the big world: The immune system copes with its functions quite well, and the body’s heat regulation also improves its functioning. The baby's weight is now about 1200 g, and his height reaches 39 cm.

Such dimensions significantly reduce the free space in the uterus and all movements of the fetus are expressed in infrequent pushes with arms and legs.
The organs and systems of the small organism continue to improve; for example, up to 500 g of urine is excreted by the kidneys every day.

falls on the cardiovascular system, although the blood circulation of a little person is not yet the same as the blood circulation of a newborn.

With the beginning of the 29th week, the amount of vernix lubrication begins to decrease, and the skin becomes increasingly lighter and smoother.

Thirtieth week (204-210 days)

The child’s weight 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 increasingly straightens the folds in the skin.

Lack of space in the womb forces the baby to take a certain position: curl up and cross his legs and arms.
Also continue alveoli develop, surfactant is actively produced, that is, the child is preparing to start breathing independently.

Brain development is characterized by the appearance of a large number of convolutions and an increase in the area of ​​the cortex.

Nerve cells function, fibers are formed, around which a protective myelin sheath appears.

The child's liver accumulates iron, thanks to which the baby will be supplied with blood cells throughout the first year of his life.

Thirty-first week (211-217 days)

The baby, who by this time already weighs 1500-1700 g and has a height of 40 cm, has significantly changes in wakefulness and sleep patterns.

Motor activity decreases, although the child kicks well while awake. 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 nerve cells, and the nerve fibers continue to be “overgrown” 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 stage.

Now the baby weighs approximately 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 milk production 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 case of early birth at this stage the baby will be able to breathe without assistance. He weighs approximately 2 kg and is 43-44 cm tall.

All parts of the body become more proportional in relation to each other, and systems and organs continue to improve (for example, the mass of the heart increases and the tone of blood vessels increases). The position of the baby's body is fixed in the uterus (he can turn his head or butt down), usually after that he will no longer turn over.

Thirty-fourth week (232-238 days)

The baby’s body weight has already reached 2-2.5 kg, and the body length is at the level of 44-45 cm. Despite the fact that he is practically no different from a newborn, the body is still continuing to improve all its parts.

Cranial bones remain just as soft and mobile, which is necessary for unhindered passage of the birth canal at birth. Increased hair growth begins on the head and it can even change color.
Also worth noting intensive 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 gains 25-35 g daily, which is why the weight can vary significantly and by 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.

There is already a fairly large amount in the fetal intestine meconium, which usually goes away 6-7 hours after birth. The baby is actively training to suck the mother's breast - he sucks fingers (even on his feet) and swallows amniotic fluid.

Thirty-sixth week (246-252 days)

Weight and height The already almost fully formed child is now very different and can range 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, the cranial bones remain just as soft and have so-called movable "fontanelles". All organs and systems completely ready for his 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 possible slight deviation from this value. The skin has already brightened well and thickened, and the fat layer increases daily by 14-15 g per day.
The cartilages of the ears and nose become denser and more elastic, maturation ends lungs and digestive system. From this moment on, even if labor begins, it will no longer be considered premature.

Thirty-eighth week (260-266 days)

It is likely that at this stage your baby will be born, but even if this does not happen, then it’s okay if he grows a little more in the womb.

No special processes at 38 weeks already not happening, baby only gaining weight. All his organs and systems are already fully developed and fully functioning.

Thirty-ninth week (267-273 days)

Normally, two weeks before the expected due date, baby starts to go down, increasingly pressing against the bones of the pelvis. It is already fully matured and the placenta begins to gradually age, as a result of which all metabolic processes in it significantly deteriorate.
Baby's weight increases daily 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.

Ongoing development of the child's central nervous system, although this process will continue after his birth. During this period, amniotic fluid is renewed every 3 hours, although its 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 either earlier or later than the due date.
At that time all indicators of its development fully correspond to the characteristics of a newborn baby. Body weight ranges from 2.5 to 4 kg or even higher, and height averages 49-52 cm.

There are intermittent contractions of the uterus, which the woman feels as episodic nagging pain in the lower part. The baby's skull bones are still soft and pliable.
Having gone 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.

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The birth of a new life is the most beautiful secret of nature. What could be more mysterious than the development of a child in the womb? The formation of a little person from a fertilized egg goes through a rather complicated path. Expectant mothers will be very interested to know how the child’s intrauterine development occurs week by week.

Initial development of pregnancy

Pregnancy lasts 40 weeks or 10 obstetric months. The term “obstetric month” implies 28 calendar days. But the beginning of pregnancy itself is considered the first day of the menstrual cycle. Thus, according to medical calculations, pregnancy lasts not 40, but 38 weeks.

So, fertilization occurred: the sperm penetrated the egg and formed a single cell with two nuclei. These nuclei, moving towards each other, form a zygote. A zygote is a one-celled embryo. This fact is the beginning of the development of a new life.

The zygote lives for 30 hours, after which its first division occurs. In subsequent days, cell division is repeated. On the fourth day of life, the embryo consists of 8-12 cells. By this time, this small lump reaches the uterine cavity, where the process of cell division intensively increases.

By the seventh day, the embryo already consists of hundreds of cells. On the eighth day, the embryo attaches to the wall of the uterus, where its walls have acquired a loose and thickened structure. The implantation process takes about 40 hours.

On the 14th day of the embryo's life, its back part thickens, preparing for the formation of the main organs.

Already in the second week after fertilization, pregnancy can be determined using tests. Already on the 3rd day of its life, a small embryo begins to produce a hormone - gonadoprin. All pregnancy tests are sensitive to this hormone.

At the end of the 4th week, a woman notices the absence of menstruation. The first symptoms of pregnancy will appear: nausea, dizziness, drowsiness.

During this period, the embryo is already called an embryo, the size of which is about 1 mm.

The development of a child in the womb can be divided into three main periods:

• Blastogenesis - the first 15 days.
• Organogenesis is the development of the embryo from 15 days to 10 weeks of pregnancy.
• The fetal period is the development of the fetus in the womb.

If we divide the entire pregnancy into 3 equal periods, we get the following time periods: first, second and third trimesters. Each trimester lasts 3 months.

If a woman is not yet aware of her “interesting situation” and continues to lead an inappropriate lifestyle, then the embryo will most likely die at the blastogenesis stage. If the mother's destructive lifestyle does not change during the first 12 weeks, there is a high probability of miscarriage.

Embryonic development of a child in the womb

Embryo development is a key moment of pregnancy, since during this period all vital organs are formed, which will affect the baby’s health in the future.

Mommy should never be nervous: only peace and positive emotions!

By the end of week 5, the embryo consists of three cell layers: ectoderm, endoderm and mesoderm. Ectoderm is the basis of the nervous system, hair and skin. The endoderm will develop in the future into the gastrointestinal tract. The mesoderm will turn into skeletal and muscle tissue, and will also form the basis of the circulatory, excretory and reproductive systems.

At week 5, a kind of heart tube is formed. We can assume that from this moment the embryo’s “heart” begins to beat.

A groove is formed on the back of the embryo, which is the basis of the spinal cord and the entire nervous system. It is very important for the expectant mother to take enough folic acid during this period. This substance promotes the full formation of the nervous system of the unborn child.

At week 6, the embryo takes on a C-shape. During this period, the formation of the primary intestine, skeletal cartilage, liver, kidneys, and thyroid gland occurs. The small embryo reaches 4 mm.

At the 7th week of pregnancy, women experience toxicosis. This period is characterized by intensive development of the brain. The mouth and eye sockets begin to form. The respiratory system actively develops, the heart begins to divide into chambers and arteries, and the spleen and gall bladder are formed.

At week 8, ultrasound can record the first movements of the embryo.

At week 9, the fingers on the upper and lower extremities are visible, although they are still webbed. This period is characterized by the fact that the placenta begins to supply the embryo with nutrients and take away waste products. The embryo already has taste sensations.

At week 10, the membranes between the toes disappear and the tail disappears. The gender of the child is still difficult to determine at this age, but boys are already beginning to produce testosterone.

By the 11th week, the embryo weighs 5 g and measures 3 cm. This is the final stage of embryonic development; the embryo will subsequently be called a fetus.

Intrauterine development of a child by week in the second trimester of pregnancy

At 12 weeks, almost all organs of the fetus have formed and the child begins to actively move inside the uterus.

This is the beginning of the third period of fetal development. At this time, as a rule, an ultrasound is performed, which determines the quality of the child’s development and genetic abnormalities.

If intrauterine abnormalities are detected in the fetus, the woman is recommended to undergo additional tests. But final conclusions about chromosomal abnormalities can be made at 20 weeks with a control ultrasound. If serious pathologies are confirmed, doctors recommend terminating the pregnancy.

It is also worth noting that the older the parents, the higher the risk of developing pathologies in the child. However, in this case, the opposite may be true: the percentage of talented children born is higher among older parents.

At week 13, the external genitalia differentiate. However, they can be distinguished already at 14-15 weeks using ultrasound. At this stage, the formation of the intestines occurs. The baby receives nutrition through the umbilical cord.

From the 14th week, the baby’s skeleton begins to form, which was previously represented by cartilage. The length of the arms corresponds to the proportions of the body, and the legs are formed with some delay. The baby can yawn and suck his thumb. He perceives the vibrations of sounds, distinguishes well the timbre of his mother’s voice and music.

That is why it is important for expectant mothers to listen to beautiful classical music, thus instilling in the baby good taste.

At week 15, the blood vessels of the fetus become noticeable, visible through the thin skin. The skeleton and bone marrow continue to form.

At 16 weeks, a routine ultrasound is performed, where you can notice the movement of the baby’s eyes. The legs have become proportional to the length of the body and small marigolds begin to grow.

At 17-18 weeks, the small body is covered with primary fluff - lanugo. This is a natural lubricant that protects the skin from the aquatic environment. During this period, fingerprints are laid, which are genetically predetermined.

The baby weighs 200 g and is 14 cm tall.

At 19-20 weeks, fetal growth begins to slow down somewhat. At this stage, subcutaneous fat is deposited, which keeps the small body warm. The respiratory system is improving more and more, but it is not yet able to function independently.

Mid-pregnancy: intensive fetal development

Starting from the 20th week, the baby's teeth begin to form. The baby's hairs on his head grow more actively, but their pigment is formed a little later.

From 22 weeks, mothers begin to feel the baby pushing. His weight at this stage is 450 g, and his height is 19-20 cm.

From 23 weeks the baby begins to gain weight. The child begins to see, he even dreams. The brain is actively developing.

The muscular system and internal organs continue to actively improve. The respiratory system is becoming increasingly developed. The first feces - meconium - accumulate in the baby's intestines.

The baby's skin is red and wrinkled. The child actively reacts to the position of the mother’s body and to external sounds. Taste buds have already formed on the tongue, thanks to which the child develops food preferences. It is important for mothers to understand this and try to avoid spicy and bitter foods, since the little one prefers sweets.

The beginning of the third and final trimester is week 27. By this time, all the organs of the fetus have already formed, and in the future they will be improved, as well as the development of the brain.

At week 29, the baby’s immune system is formed. The heart rate reaches 120-130 beats per minute. The baby may hiccup, as evidenced by slight tremors to the mother.

A child born at this stage can survive with certain care. His height is 37 cm and weight is 1150 g.

Prenatal development of the child in the last stages of pregnancy

For women who are preparing to become mothers of a healthy baby, it will, of course, be superfluous to talk about the right lifestyle. Alcohol, cigarettes, lack of routine, sleep and rest have a very detrimental effect on the health of the unborn child.

At 30-32 weeks, the baby’s subcutaneous fat layer becomes thicker. Some babies are already turning head down at this stage.

Convolutions appear on the surface of the small brain. The pupils can already detect bright light. When performing an ultrasound at this stage, you can notice how the baby closes its eyes from bright light. For this reason, it is important to avoid ultraviolet rays and avoid beach holidays.

From the 33rd week, the little man already becomes cramped in his mother’s tummy. At this stage, the fetus turns head down, preparing for birth.

If premature birth occurs at this stage, the baby has every chance of survival. However, he will be considered premature and will need special care in the hospital.

The baby's skin becomes pink and not so wrinkled, thanks to subcutaneous fat. It makes up 8% of the total body weight.

Thanks to the appearance of marigolds, the baby can scratch himself. Some newborns are born scratched.

From the 37th week there is an active improvement of the respiratory system. Babies born during this period can already scream. The vellus hair on the body thins, and on the head it grows rapidly. The child gains 30 grams of fat every day.

By this time, the stomach drops, and it becomes easier for mom to breathe. This usually happens two weeks before birth.

By this time the baby is ready to see the light. He is very cramped inside his mother: his knees are pressed tightly to his chin.

At week 39, the body becomes clean: the fluff remains only on the shoulders. The baby's intestinal system is filled with meconium and amniotic fluid.

At 40 weeks, prenatal development ends and a new person is born! Photos of newborns become almost the most important photo in the house. After all, what could be more exciting and beautiful than the birth of a small miracle!

Pregnancy is a complex and long physiological process, during which amazing metamorphoses occur - a new organism, a completely unique creation of nature, is formed from a pair of cells.

Many expectant mothers, those who are planning a pregnancy or are already carrying a child, need to know what changes are occurring in their body in order to take into account all the risk factors that affect the correct development of the unborn baby.

Duration and stages of pregnancy

On average, a human pregnancy lasts about 280 days or 40 weeks, this period is counted from the last menstrual period. A child born earlier or later with an amplitude of three weeks is premature or post-term.

Traditionally, the prenatal period is divided into two stages:

Also in gynecology, it is customary to consider the course of pregnancy through the prism of trimesters:

• the first trimester conventionally lasts 12 weeks, starting from the moment the male and female cells meet; it ends with placentation - the beginning of the functioning of an irreplaceable organ during this period of a woman’s life - the placenta;
• second trimester – from the 12th to the 27th week – the stage of maturation of body systems (central nervous, immune and others);
• the third trimester - from 28 to 40 weeks - is a period of preparation of internal organs for extrauterine life.

Doctors separately identify the “critical”, most responsible and complex stages of development:

• the period of implantation and the beginning of cell division (from the moment of conception to 2 weeks);
• the period of formation of internal organs and placenta (from the 3rd to the 8th week);
• period of easy permeability of the “baby spot” (from the 32nd to the 36th week).

Let's consider a detailed description of the development of the fetus and the woman's sensations by week of pregnancy.

First trimester (up to 12 weeks)

The countdown of fetal development begins precisely from the moment of conception, which occurs in the third week of the last menstruation. For the previous 14 days, the woman’s body has been actively preparing for this event - this happens monthly, and is marked by the beginning and end of menstruation.

During this time period, the egg matures and begins its journey through the fallopian tube, ovulation occurs.

Week 1 - conception and the beginning of cell division

Fetal development

The history of any human body begins with the meeting of male and female reproductive cells. After passing into the fallopian tube, the egg “lives” for only a day, while sperm remain in the body for another 2-3 days after unprotected sexual intercourse.

When these cells merge, a zygote is formed, which moves towards the uterus within 3-4 days to begin growth.

Cell fragmentation occurs at a tremendous pace - if a 3-day embryo contains 8 cells, then a 4-day embryo contains as many as 20. The cells are not yet fully organized and represent a hollow ball.

Woman's condition

At the same time, it seems to the woman that “menstruation” is about to come: the breasts become more sensitive, the condition resembles premenstrual. At the same time, a regular pregnancy test will not give the correct result; only a laboratory blood test can help those who are especially impatient.

Ultrasound will also give productive results - in a short period of time it becomes known exactly where the embryo will be implanted.

A slight increase in temperature may also indicate pregnancy.

Bloody discharge at this stage may indicate both a miscarriage and menstruation (according to statistics, about 30% of women have regular periods after pregnancy). However, intense bleeding and sharp pain are symptoms of miscarriage, in which you need to urgently contact a gynecologist.

Week 2 – implantation

Fetal development

At the border of two weeks - the 7-8th day - the embryo is implanted into the uterine tissue - the endometrium, which will be a source of nutrients for a long time. The “implementation” itself is sometimes accompanied by slight hemorrhage, since the integrity of the tissue is disrupted.

Next, the fertilized egg moves to the stage of cell grouping - they are all divided into three layers, among which the inner one - in the future will form the lungs, liver, digestive organs, the middle one - the skeleton and circulatory system, and the outer one - the nervous system, skin, etc.

Woman's condition

Due to the fact that human chorionic gonadotropin begins to be actively produced, it becomes possible to find out about pregnancy using a regular pharmacy test. The breasts become more sensitive, and general symptoms still resemble premenstrual symptoms.

On an ultrasound, it is easy to see the corpus luteum, which performs the function of the placenta.

Since it is in the fourth week that a woman first begins to suspect an “interesting situation,” it is better not to delay diagnosis in order to promptly detect an ectopic pregnancy.

The cervical canal is filled with a mucous plug that protects the baby from infectious diseases. The discharge is normally transparent, but during implantation there may be minor blood discharge. Also, when pregnancy occurs, women’s immunity often decreases, and the flora itself becomes favorable for “thrush” - hence the possibility of copious curdled discharge. The fungus is easily treated without consequences for the fetus.

Week 3 – first heartbeats

Fetal development

On the 3rd week, the neural tube - the basis for the spine - begins to close, the spinal cord and brain begin to form, and on the 21st day a significant event occurs - the tiny heart begins to beat.

The gonads, eggs and sperm also begin to develop. The child is actively growing

Woman's condition

If during the previous week a woman has little idea about her condition, then the 3rd week is often indicated by the arrival of “toxicosis”. In addition, the body quickly gets tired, eating habits change, mammary glands swell, and mood changes.

An ultrasound and test can give a complete picture of the presence of a fetus in the uterus, and a blood test for hCG and progesterone will help identify potential threats of miscarriage.

Menstruation at this time is more a rarity than a rule. Normally, the discharge is transparent, and “candidiasis” is also likely to occur. Changed color and smell of secretions indicate infectious and sexually transmitted diseases.

Week 4 – organ laying

Fetal development

The foundations for internal organs are laid, the heart rate accelerates, the rudiments of arms and legs are formed, and most importantly, the neural tube is transformed for brain growth. The transition to placental nutrition is gradually being prepared, the corpus luteum loses strength, and the placenta is connected to the fetus by the umbilical cord.

Woman's condition

A woman should be prepared for the fact that toxicosis will haunt her until the end of the 12th week, since male cells are foreign to the body. Often, a pregnant woman begins to suffer from back pain associated with changes in body weight and restructuring of the body.

At this stage, the gynecologist will offer all kinds of tests, which should not be neglected.

Bloody, greenish, yellowish and other discharges are not normal. The uterus increases slightly in size, but the changes are not yet noticeable.

Week 5 – first movements

Fetal development

The heart is divided into two chambers, metamorphoses of the reproductive system are observed.

The brain is divided into two hemispheres, facial features are improved - the nose, eyes, mouth are designated.

The arms can bend and the beginnings of fingers grow. The embryo makes the first small movements, but this is not noticeable to the mother.

The umbilical cord completely completes its formation, the placenta acquires a dense structure.

Woman's condition

The ligaments supporting the uterus are stretched, causing slight pain in the lower abdomen. The pigmentation of the skin around the nipples increases, and the urge to urinate becomes more frequent. Possible problems with digestion. The nature of the discharge should be carefully monitored. The uterus has already reached the size of a small egg, but pregnancy is completely invisible.

Week 6 – continuation of organogenesis

Fetal development

The heart is being upgraded to a four-chambered one. The lungs and bronchial tree develop. Unique facial features appear, eyes continue to form, and the iris takes on color.

The phalanges of the fingers grow, the unborn child can fully bend and straighten them. The intestines are already so large that they do not fit in the abdomen - part of it is in the umbilical cord. The genital organs have a different appearance, but this is not yet visible on ultrasound.

Mother's condition

A young mother should choose new underwear as her breasts are rapidly expanding. Increased drowsiness and irritability. The condition of the skin changes. During examination, the uterus can already be palpated, the pharynx is completely closed with a plug.

Week 7 – formation of glands

Fetal development

In the seventh week from the moment of conception, the tail at the base of the spine disappears.

The placenta begins to produce hormones on its own, supporting intrauterine processes. Large blood vessels and endocrine glands complete their formation.

Time of formation of the pituitary gland, cerebellum, middle layer of the adrenal glands and lymph nodes.

The child begins to wrinkle his face and swallow. The neck emerges.

Mother's condition

The mother's kidneys will henceforth work double duty as the baby's urinary system develops. At the same time, the body begins to accumulate fat reserves. The uterus expands to the size of a tennis ball, so a woman can feel it while exploring her body.

Week 8 – completion of organogenesis

Fetal development

The eighth week is one of the most important, since the formation of all vital organs and tissues is coming to an end, the main crisis stage is completed. Next, the child will only gain weight and height.

The dimensions of the fetus do not exceed 4 cm, but it is already a fully formed organism with fingers, knees, elbow joints, ears and a mouth. Normally, the child already knows how to bring his fist to his mouth.

The nervous system is quite developed by this time, therefore, according to numerous studies, the baby is able to feel physical pain.

The rudiments of baby teeth are just forming. Boys are already producing their own testosterone, and girls are laying eggs - their number is certain for the rest of their lives.

It is this week that the doctor will suggest doing the first diagnostic ultrasound before screening, since thanks to the technology it is possible to find out whether the child has severe genetic diseases - for example, Down's disease.

Mother's condition

The uterus gradually begins to rise above the pubic joints, preparing to increase in size.

Week 9 – end of the embryonic period

Fetal development

The embryonic period is over and the baby will now begin to grow at a rapid pace.

The heart is functioning fully, the blood vessels are fully formed.

The liver develops, the intestines make the first movements that faintly resemble peristalsis.

The fetus tries to move its head, a weak sense of smell appears, which will help find the breast at birth. The baby begins to move around the uterus in free swimming, respond to movements, sounds, and grab the umbilical cord.

Mother's condition

Toxicosis disappears. It becomes uncomfortable for a woman to sleep on her back, and a feeling of constant thirst appears as the volume of amniotic fluid increases.

Week 10 – screening

Fetal development

The main systems of the body are fully formed, all organs are actively working and improving. The first hair covering appears - vellus hair. The child leads an active lifestyle, grimaces and waves his arms. The glands begin to function, the intestines are able to contract, and the liver secretes bile.

The tip of the nose is taking shape, the ears are still displaced.

Mother's condition

The uterus is actively growing, slightly crowding the intestines and bladder. At this stage, the mother will be offered a comprehensive screening to exclude the presence of developmental defects; an ultrasound and biochemical blood test are performed. Screening can detect serious genetic diseases, and some parents will have to make difficult choices between continuing or terminating a pregnancy. Especially experienced ultrasound specialists are able to predict the gender of the unborn baby.

The ligaments in the abdomen and lower back suffer most from sprains, which is associated with the upward transition of the uterus. The amount of leucorrhoea increases sharply, while other types of discharge can accompany diseases.

Week 11 – the beginning of the development of emotions

Fetal development

The first and most important trimester is coming to an end, the child’s height is already 7 or 8 cm. Muscle and bone tissue are improving, the digestive system is acquiring villi, which will soon move food. The male reproductive organ lengthens and the prostate gland develops. The rudiments of baby teeth are fully formed in the gums. The pancreas is responsible for producing insulin.

The most important achievement concerns the emotional sphere - the child listens to new sounds, smiles, and hardly sleeps. Movements of arms and legs are still chaotic. The baby can already distinguish the taste of food and has taste preferences.

Mother's condition

The second trimester begins - the calmest time of pregnancy. The fetus is not yet so heavy that walking seems difficult, and the body no longer perceives male reproductive cells as something foreign. However, an enlarged uterus leads to heartburn and problems with bowel movements. Starting from this period, the gynecologist will measure the abdominal circumference and the height of the uterus.

Second trimester

The created organ systems are only fine-tuning their work. From the 22nd week, neonatologists are able to deliver the baby in case of premature birth. This stage is characterized by intensive growth of the fetus and the development of higher brain structures.

Week 12 – gender recognition

Fetal development

Facial features continue to change - the ears have moved to their proper location. It finally becomes possible to recognize gender, since the external genitalia are finally transformed into male and female types.

The child's height is almost 10 cm, but his movements are not yet noticeable to the mother. The fetus acquires ribs, and their movement increasingly resembles rising and falling during breathing.

The hairline consists of eyelashes, eyebrows, scalp hair and “lanuto” - a thin fluff designed to retain a special thick lubricant on the skin that helps pass through the birth canal.

The muscles are so developed that the baby is able to push off from the abdominal wall, which does not go unnoticed by thin girls.

Mother's condition

The child consistently takes away most of the nutrients from the woman, which negatively affects the condition of the hair, teeth and gums. Already at this stage, many women notice the appearance of stretch marks. The uterus is located between the joint and the navel, it can be easily felt by simply placing your hand on your stomach. The edge rises 13 cm above the pubis.

Week 13 – complication of the cerebral cortex

Fetal development

The brain surface is covered with convolutions and grooves, and nerve cells quickly divide. The sweat glands begin to work. The baby actively absorbs nutrients and urinates in the amniotic fluid.

The heart beats about 150 beats per minute, pumping almost 30 liters of blood.

From this week, the child begins to exercise his lungs by inhaling and spitting out liquid. The glottis opens - the baby is preparing for the first cry. The cub performs a number of acrobatic tricks, building up its muscles.

The placenta begins work, now supplying oxygen, removing waste, producing its own progesterone and estrogen. The child's eyelids are still closed.

The bone marrow begins to produce white blood cells - the immune system prepares to protect the baby after birth.

The bone tissue hardens, and the skin becomes multi-layered, albeit transparent. The fetus gradually takes on a human appearance - the body and limbs lengthen. Height exceeds 10 cm.

Mother's condition

At this stage, a second screening is carried out. The second trimester biochemical test gives more accurate results. Since the study provides only a presumptive result, amniotic fluid sampling is recommended for women over 30.

Week 14 – first movements

Fetal development

The child’s height exceeds 11 cm. By this week the composition of the blood corresponds to that of an adult, as the bone marrow begins to produce blood cells. Regular hemoglobin also appears in the blood. The thyroid gland develops, which reproduces thyroxine and triiodothyronine, preparing the body to digest proteins and begin storing fat, which will appear next week.

The liver, which was previously involved in hematopoiesis, begins to perform a digestive role, and the remaining organs carry out “training”. Original feces, consisting of bile, accumulate in the child’s intestines. Urination occurs almost every 40 minutes.

The fingernails have almost taken shape. The face “humanized” as the eyes moved to their designated place.

Mother's condition

At this stage, the woman first feels that life has arisen inside her. Fetal growth leads to increased appetite. The weight of the uterus reaches 250 grams, the protrusion reaches the distance to the navel.

Week 15 – period of hyperpigmentation

Fetal development

This week the fetus acquires fat, which is involved in the heat exchange process. Its own immune system comes into play, immunoglobulin and interferon are produced - the child is able to protect himself from infections if the mother gets sick.

The height is 13 cm. In girls, the uterus gradually forms. The formation of permanent teeth begins, which “stand in line” behind the milk teeth.

The nervous system is mature enough to begin to communicate with the child, who is able to recognize the voices of people close to him, recognize music, as well as the mother’s bad mood.

Mother's condition

The uterus is constantly growing, the woman suffers from frequent urination and shortness of breath. The organs must be somewhat crowded, which leads to heartburn and digestive problems. The stomach begins to protrude and it becomes impossible to sleep on it. Normally, a woman begins to gain 200-300 grams per week.

Week 16

Fetal development

The heartbeat can be clearly heard using special equipment, the fetus reaches a height of 14 cm. The growth of eyebrows and hair on the head continues. The skin is fully formed, but it is so tender that the circulatory system is completely visible.

The fetus floats freely in the amniotic fluid, and the salivary glands begin to work. The reaction to light and sound improves, so it is better to avoid loud sounds. The child turns his head and jerks his arms. Scientists believe that such gymnastics has a positive effect on the mental development of the child.

Mother's condition

The mother should monitor the baby's movements - if movements occur more often than 4-8 times per hour, then this indicates oxygen starvation. The size of the uterus is similar to a small melon. The severity of the fetus affects the functioning of the woman’s musculoskeletal system - the pregnant woman’s gait changes.

Week 17 – improving neural connections

Fetal development

The neurons debug the interaction system, as a result of which the baby learns to control the eyeballs. The child's movements become more coordinated. The bronchial system is completing its formation. The sebaceous glands continue to work, covering the body with a white-gray lubricant and accumulating in the folds. The fluff grows throughout the body and disappears closer to childbirth.

The baby's neck is strong enough to turn 180 degrees. The baby's height exceeds 15 cm. The baby's weight finally exceeds the weight of the placenta. The skin is still very thin, and you can now see brown fat underneath it. The immune system begins to function at full capacity.

Mother's condition

The breasts increase significantly, hormones provoke the flow of blood to the mammary glands. The uterus weighs more than 300 grams and continues to rise. The mother's weight increases to 6 kg.

Week 18 – improved hearing

Fetal development

The baby's inner ear, which was previously too primitive, finally completes its formation - small bones appear. The retina of the eye becomes photosensitive, the eyeball is ready for contemplation, and the blink reflex appears. However, the eyes are still closed.

The bone tissue continues to harden. The abdomen and buttocks become very sensitive. The teeth are covered with dentin. From this time on, the child begins to sleep for a long time, sleep acquires phase division.

Mother's condition

Leg cramps may occur due to weight gain. The uterus protrudes 12 cm above the womb. Meanwhile, some women have training contractions that have no effect on the baby.

Week 19

Fetal development

At this stage, the baby’s height exceeds 16 cm, weight is about 300 grams, and the fruit is the size of a small zucchini. The body is still covered with a cheese-like lubricant that protects the skin from amniotic fluid. The child can touch his own face, amniotic sac, tug at the umbilical cord, and kick it. It is already known whether the baby will be left-handed or right-handed.

The group of nerve cells responsible for the sensory organs is fully formed. The child begins to interact with the outside world, responding to loud sounds with blows. Any stress is accompanied by an increase in activity. Meconium is actively accumulating in the intestines, which will be released after birth.

Mother's condition

The mother's body undergoes enormous changes, the cardiac impulse increases, the pulse quickens, the blood volume increases, which causes the hemoglobin level to decrease and the number of red cells to decrease. The woman is plagued by lumbar pain, the uterus puts pressure on the bladder, causing stagnation of urine, which risks turning into pyelonephritis, which threatens the fetus. Often the symphysis becomes inflamed due to weight.

Week 20

Fetal development

By the end of the twentieth week, growth reaches the 20 cm mark. Under a protective layer of lubricant, skin cells are actively dividing, forming layers of the epidermis. The child distinguishes day from night and becomes active at different times of the day. The eyes are closed, but this does not prevent the baby from being well aware of the environment - according to research, twins and twins can hold each other's hands.

The spine has acquired intervertebral discs, the fetus tilts its head if desired, and movements become more complicated. The child may try to signal to the mother if he is dissatisfied with the location or the sounds are too loud.

Mother's condition

By the end of the second trimester, an even more unpleasant phenomenon may appear - hemorrhoids. In addition, the mother can feel training contractions, but they should not be accompanied by severe pain. The uterus is already resting against the diaphragm, shortness of breath appears.

Week 21

Fetal development

The child’s weight increases by 100 g, becomes about 350 g, the size of the fetus is about 25 cm. The child feeds and breathes amniotic fluid, while the amniotic fluid changes composition every 3-4 hours.

Taste buds complete their formation on the tongue. The eyeballs are actively moving. The intestines begin to absorb and metabolize carbohydrates. The bone marrow finally replaces the spleen and liver as the producer of blood cells.

The teeth are prepared for the formation of enamel. The boy's testicles begin their journey from the abdominal cavity. Girls develop a vagina. At this stage, a lack of amniotic fluid or polyhydramnios may be detected - both are harmful to the fetus and require correction.

Mother's condition

At this stage, the mother needs more calcium than ever. Lack of proper nutrition will affect the condition of the teeth and provoke cramps in the legs. Many women suffer acutely from anemia. Appetite increases. The uterus compresses the inferior vena cava, causing the legs to constantly swell.

Week 22

Fetal development

The height of the fetus is 28 cm, weight – 500 grams. Premature birth at 22 weeks can end happily - medicine allows such a child to be born without serious developmental problems. The baby's brain reaches a weight of 100 grams. The alveoli of the lungs become mature and produce a substance that prevents compression during breathing.

The baby fills the entire uterine cavity, stretching it. The skin gradually produces pigment and fingerprints appear. At this stage, an indication for a caesarean section may be gestational diabetes - low blood sugar, so additional tests are carried out.

Mother's condition

The mother should closely monitor weight gain and discharge. During this period, leakage of amniotic fluid is especially dangerous. The baby moves actively and lying down for a long time is not encouraged - this can lead to entanglement of the umbilical cord.

Week 23

Fetal development

The child’s weight reaches 600 grams, and independent production of growth hormone begins. The baby's skin is very wrinkled. Rapid growth of adipose tissue occurs. The arms lengthen and the nails grow, which will need to be trimmed carefully after birth. The hair becomes pigmented.

The genitals continue to develop - the testicles in boys gradually descend. The frequency of fetal movements is about 10 times a day. According to research, it is during this week that the nervous system undergoes changes that allow the baby to dream. The spleen is actively involved in hematopoiesis, producing leukocytes and monocytes.

Mother's condition

Due to the production of progesterone, side effects such as blocked veins, swelling of the limbs and bloating are possible. From about this time, women suffered from severe heartburn. They undergo the final screening - ultrasound and blood biochemistry.

Week 24

Fetal development

The baby's height is already 30 cm. By this age, the child turns over and is head down. The child sleeps for about 15-20 hours. The eyes are covered with a thin film. The movement becomes more distinct as the baby pushes against the walls of the uterus. However, there are cases when the placenta is attached along the anterior edge.

The baby is still practicing breathing and the lungs are producing more surfactant. The amount of amniotic fluid is 400 ml. Sometimes the baby starts to hiccup, and the mother feels it. This is caused either by improper ingestion of amniotic fluid or by hypoxia.

Mother's condition

The pelvic bones expand, and fatigue appears from long walking. You should monitor excess weight so as not to lead to gestosis, which negatively affects the child.

Week 25

Fetal development

The size of the fetus is approximately 33 cm, weight - about 700 g. The baby's skin acquires color and becomes dense.

The lungs are exercising, but if born prematurely, the fetus will not be able to breathe on its own.

Boys' testicles already reach the scrotum. The fetus develops a grasping reflex.

The brain establishes communication with the adrenal glands.

Mother's condition

The mammary glands begin to produce colostrum, but this does not happen in all women. Symptoms of pregnancy are normal: heartburn, constipation, lower back pain, cramps, swelling, shortness of breath, deterioration of teeth and hair.

Week 26

Fetal development

The baby's height is 35 cm, weight - almost 800 g. Fetal kicks become painful. Hearing becomes more subtle. The child's activity increases as he becomes stronger.

Mother's condition

With weight gain, all of the listed pregnancy symptoms only intensify, and cramps appear in the calf muscles. The doctor can diagnose gestosis, expressed in swelling, headaches, nausea, vomiting, hypoxia, as well as oligohydramnios or polyhydramnios, increased uterine tone. All these phenomena are in most cases treated with medication.

Week 27

Fetal development

At week 27, the baby outgrows 35 cm in height and weighs 1 kg.

In a dream, a child is already capable of smiling for the first time.

Vellus hair disappears from the skin, remaining only in the shoulder area.

Mother's condition

The fundus of the uterus rises to a height of about 30 cm above the womb, so the mother has difficulty breathing. It is necessary to prevent blood stagnation and walk more.

Third trimester

The final, but less important stage of pregnancy begins. Organogenesis is complete, the baby is preparing for its first breath. From now on, if premature birth begins, there is a high chance of saving the child.

Week 28

Fetal development

The neck lengthens. The skin gradually smoothes out due to fat. The bones remain flexible, although the entire fat tissue system has formed. Hair lengthens and its pigmentation intensifies.

The pupillary membrane disappears from the eyes, the child learns to open his eyes, actively reacting to light. The baby begins to distinguish between sour and sweet.

Mother's condition

A woman at 28 weeks may feel like she is feeling hot and cold. This is due to the new metabolic rate and helps remove toxins from the body. At this time, the doctor examines the placenta and makes a conclusion about its age.

Premature aging is an indicator for a cesarean section. Insufficiency of nutrients in the placenta is expressed in a decrease in the child’s motor activity, a smaller abdomen, and increased uterine tone.

The doctor can also detect placenta previa; if it closes the internal os, bleeding is possible. If changes in location did not occur before birth, then a cesarean section is performed.

Week 29

Fetal development

The baby's weight exceeds 1 kg, height is about 40 cm. The baby is quite ready for birth and is formed externally. The amount of original lubricant on the skin decreases, and the characteristic fluff disappears. The so-called “white fat” accumulates, which is especially abundant on the face, to support the baby’s ability to suck.

The kidneys secrete about 500 g of urine, which still partially ends up in the respiratory tract and digestive system. Mucus plugs disappear from the nose. The baby actively receives antibodies from the mother's blood.

Teeth are located in the gums, but some babies are born with them.

Mother's condition

The mother's weight gain should not exceed 300-400. It is especially important that fluid is not retained in the body, since edema can manifest itself not only externally, but also in internal organs.

Week 30

Fetal development

The baby weighs about 1.4 kg. Height is about 40 cm. The child continues to develop lungs, sometimes the liquid gets into the wrong throat, then the baby begins to hiccup rhythmically. Nutrition occurs through the placenta, which weighs about 600 g.

The umbilical cord consists of two umbilical arteries and one vein. As the child moves, umbilical cord nodes may form, which become tightened and cut off the baby’s oxygen. Such cases are rare, but it is precisely with them that doctors’ recommendations for tracking the frequency of fetal movements are associated.

The brain completes the formation of furrows. The liver accumulates iron. At birth, the baby can be easily carried to term.

Mother's condition

Leakage of fetal fluid is possible; if you suspect it, you should not hesitate to send it to the hospital. The uterus rises 8-10 cm above the pubic bone. The breasts may also begin to leak colostrum.

Week 31

Fetal development

The baby weighs about 1.5 kg, height - more than 40 cm. The child takes the final position upside down, but there are also cases of breech presentation.

The kidneys actively excrete urine into the amniotic fluid. A protective sheath is formed around the nerves, impulses are transmitted faster, and the child begins to assimilate the first information.

Much of your baby's sleep consists of REM sleep, which has been confirmed by multiple studies of brain activity this week, suggesting that baby is dreaming.

Mother's condition

The mother's weight increased to 10 kg compared to pre-pregnancy. A woman should pay special attention to diuresis and compare the fluid she drinks and the fluid excreted by the kidneys. Edema indicates the presence of gestosis, the most severe cases of which lead to the death of the fetus and mother.

Week 32

Fetal development

The baby already reaches a weight of 1700 g, height increases to 42 cm. The child actively sucks his finger and can already see - his eyes react to light.

The fetal arms become overgrown with fat. In addition, the baby's body begins to produce immunoglobulins, which will serve as a shield against harmful bacteria in the first months of life.

Most children turn their heads down by this age, but if this does not happen, you should wait a little and perform an ultrasound next week.

Mother's condition

The child becomes stronger, so the blows may be somewhat painful. A woman may suffer from flatulence and bloating, weakness, dizziness, and cramps. The placenta at this stage is 30 to 40 ml.

Week 33

Fetal development

There is not enough space, so the child assumes the fetal position, with his chin pressed to his chest. The child’s height is up to 43 cm, weight is about 2 kg.

The baby can see colorful dreams. The child becomes like a newborn, the baby’s eyes open slightly.

The nails have grown and protrude beyond the pads.

Thumb sucking trains children's facial expressions. The child continues to develop, stealing calcium reserves from the mother for the formation of the skeletal system

Mother's condition

Pregnancy is difficult, it increases in size, and the baby’s blows become more noticeable.

Week 34

Fetal development

The child's weight exceeds 2 kg, and hair continues to grow on his head.

The navel takes its usual place. Lines are formed on the palms. More than half a liter of urine is excreted from the body per day.

Changes in hearing occur - the baby begins to distinguish intonations.

Mother's condition

The symptoms are no different from the previous week. Sometimes false contractions begin. There is a smooth weight gain.

Week 35

Fetal development

The size of the fruit reaches 45 cm, and the weight is 2-3 kg.

The child quickly gains weight, meconium accumulates, which, however, is not released into the amniotic fluid.

The child's eye color is blue-gray.

The frequency of movements in the baby is 15 times every 24 hours.

Mother's condition

The large size of the fetus and a lack of vitamins lead to the appearance of stretch marks on the skin, severe heartburn causes loss of appetite, and difficulty breathing. Pain appears under the ribs. The fundus of the uterus rises 35 cm above the womb.

Week 36

Fetal development

The baby's height is 47 cm, weight is 3 kg. The body shape becomes more rounded. The skull has not yet ossified. The lungs are ready for independent breathing.

The genitals are fully formed - the labia majora in girls cover the labia minora, the testicles of boys have completely descended into the scrotum. Normal activity is 10 movements in 12 hours.

The child may painfully kick internal organs, which is especially unpleasant - the bladder. The fundus of the uterus occupies the highest point. It is during this week that twins are often born.

Mother's condition

The gradual descent of the fetus begins. False contractions appear. The mother becomes more clumsy. There is increased hair and nail growth, frequent trips to the toilet and swelling.

Week 37

Fetal development

Height – about 48 cm, weight – 3 kg. The baby's skin smoothes out, nails grow to the tips of the fingers. The baby may scratch himself. Cartilage becomes more elastic.

The skull does not completely ossify - the fontanelles necessary for passage through the paths remain. However, with hypercalcemia, the fontanelles become overgrown, and the baby may be trapped. To do this, it is necessary to perform an ultrasound at a later stage.

The child is already able to breathe without devices; if he is born a little earlier, the lungs are sufficiently trained. The adrenal glands are larger than the kidneys, and hormones are produced intensively.

The nervous system continues to develop, but the reflexes necessary for life have already been developed. The digestive system is covered with small villi, the stomach makes its first contractions.

Mother's condition

The woman is almost not bothered by heartburn, but nagging pain in the ligaments persists and the process of defecation becomes difficult, or vice versa - it becomes more frequent, which indicates imminent contractions.

Week 38

Fetal development

Height – about 50 cm, weight – 3 kg.

All organs are already formed, leaving little space for the baby.

The heart is actively working, but there is still a small hole between the chambers.

The movement is no longer as active, which is associated with an increase in the size of the fetus.

Mother's condition

At this stage, false contractions are possible. Frequent pain occurs due to pinched femoral nerves. Lack of calcium leads to muscle pain. Heartburn and dizziness are common. This week the mucus plug may come away, and the cervix is ​​gradually preparing for the birth of the baby.

Week 39

Fetal development

Height – more than 50 cm, weight – 3.5 kg.

The fruit at this time is the size of a small watermelon.

The skin becomes white. The stomach is filled with enzymes that can digest food.

A sucking reflex is formed. The baby develops special ridges on the mucous membrane of the lips.

The child's gaze tries to focus on flashes of light. The spinal cord and facial nerves are finally maturing.

Mother's condition

There is a feeling of severe heaviness in the perineum. The uterus descends, so breathing becomes much easier. Precursors of labor may appear.

Week 40

Fetal development

Height – from 50 cm. Weight – from 3.0 kg. The baby's body does not have any fluff, the skin becomes pinkish, the palms and heels wrinkle.

The lubricant practically disappears. The fetus occupies the entire uterus, its movements are very limited.

There is meconium in the intestines, the lungs are ready to open.

Shortly before birth, the child practically ceases to be active, entering a borderline state.

Mother's condition

The stomach gradually moves down, so it becomes easier for mom to breathe. The pelvic bones expand. The discharge becomes more abundant as the cervix opens and prepares for childbirth. There is a frequent urge to urinate. The breast is gradually preparing for feeding. As a rule, this week ends with the long-awaited birth of a child.

And more information about the weeks of pregnancy is in the next video.

We invite you not only to learn interesting facts, but also to observe for yourself, week after week, how the baby develops. The origin of life and pregnancy week by week with unique photographs that were taken by Swedish photographer Lennart Nilsson back in 1965. The photographer himself was born in 1922 and became the first who, using special equipment and cameras, was able to penetrate inside the female body and film the entire process of the birth of a new life.

The first photographs of the embryo appeared in print back in 1953, and this event inspired the photographer to create new works.

To show human development from the very beginning, he placed a micro-camera and micro-illuminator on the end of a cystoscope tube used to examine the bladder, and took his unique photographs right from where people take their first step into the world. We will talk about the most important moments of pregnancy and the formation of a new life.

“IMPORTANT” * the development of pregnancy in this article is based on the weeks of embryo development. Those. if you want to get an obstetric week, add 2 weeks to the embryonic period

Here the sperm moves towards the egg.

The sperm in the folds of the mucous membrane of the fallopian tubes moves towards the egg.

Egg..

Will the meeting take place?

The walls of the fallopian tube...

Two sperm come into contact with the shell of the egg. Enzymes contained in the head of the sperm dissolve the membrane of the egg, but only the genetic material of one sperm is involved in fertilization.

One of the father's 200 million spermatozoa, having broken through the membrane of the egg, literally pours into it...

Longitudinal section of a spermatozoon. Genetic material is contained in the head of the sperm

Pregnancy by week - 1 week

The beginning of a new life begins with a change in the female body, ovulation occurs. This moment is favorable for conception. After all, a woman can become pregnant only 3-4 days a month. Some women feel ovulation, some don't. Signs of ovulation may be an increase in vaginal mucus, an increase in basal temperature, as well as minor pain in the ovary area. Also during ovulation, under the influence of hormones, a woman, as a rule, experiences a desire for intimacy.

After a week, the embryo, sliding down the fallopian tube, moves into the uterus...

Embryo attached to the uterine lining

Pregnancy by week - 2 weeks

The fertilized egg begins to divide. Of the 46 parental chromosomes, the child inherits 23, 2 of them - X and Y - influence the gender of the unborn child. Whether you have a girl or a boy depends on the sperm that fertilizes the egg.

During this week, the embryo travels through the fallopian tube and ends up in the uterine cavity. Towards the end of the week, it attaches to the wall of the uterus, growing into its mucous membrane. Sometimes implantation may cause slight bleeding.

Embryo development. Gray - future brain

Pregnancy by week - 3 weeks

24 days. A one-month-old embryo does not yet have a skeleton - there is only a heart, it begins to pulsate on the 18th day

Pregnancy by week - 4 weeks

4 weeks after fertilization

Pregnancy by week - 4 and a half weeks

Around this time, and most likely even later, a woman finds out about her pregnancy, provided that her cycle is approximately 28 days. There is no menstruation. Possible signs of pregnancy appear, such as fatigue, drowsiness, nausea in the morning and in transport, and increased salivation.

Pregnancy by week - 5 weeks

A five-week embryo, 9 mm long, can already discern a face with holes for the mouth, nostrils and eyes. The central nervous system begins to develop, the spinal cord and brain are formed. These processes directly depend on the presence of necessary substances in the mother’s body. First of all, we are talking about folic acid - the most important element for the first trimester of pregnancy. Doctors recommend consuming 400 mcg of folic acid daily to prevent neural tube defects. By the way, by the end of the fifth week the baby’s heart will begin to beat. Only now, most likely, will the young mother begin to think about the possibility of pregnancy and take a test or consult a doctor.

Pregnancy by week - 6 weeks

40 days. The outer cells of the embryo grow together with the loose surface of the uterus and form the placenta, or baby's place. This spongy piece of flesh serves a person in the first nine months of his life as lungs, stomach, liver, and kidney...

Pregnancy by week - 7 weeks

Unlike the second trimester, when your waist rapidly expands, in the first trimester your breasts mainly expand. This happens regardless of toxicosis. Blouses and sweaters become tight, the bra is difficult to fasten.

The fetus continues to grow and develop. The brain and limbs are formed. The mass of the tiny body is already a whole gram, and the size is about a small grape. The baby is beginning to master its environment and move, but you don’t feel it yet.

Pregnancy by week - 8 weeks

The rapidly growing embryo is well protected in the mother's womb. Using an electron microscope, Nilsson was able to magnify the image hundreds of thousands of times.

Pregnancy by week - 9 weeks

Starting this week, the baby is proudly given the title “fetus.” The most common problem “threat of early miscarriage” is long gone. Everything is fine with your baby, the pregnancy is developing as it should, so the uterus is not trying to get rid of the pregnancy.

At the ultrasound, of course, they won’t tell you who you are expecting, a boy or a girl. External sexual characteristics are just beginning to form.

Pregnancy by week - 10 weeks

The eyelids are already half open. They will be fully formed within a few days. The baby is becoming more and more like a little man. Now is one of the most important periods in the development of the baby, the development of the nervous system and almost all organs is underway. The placenta does not yet completely protect the baby from adverse factors, therefore, during these weeks of pregnancy, drinking alcohol or another damaging factor can cause significant harm both to the course of pregnancy and to the development of the embryo as a whole.

Pregnancy by week - 11 weeks

Many pregnant women at this stage note that their palms and feet no longer feel cold. This is explained very simply: the amount of blood increases and its circulation improves, and the hormones produced due to pregnancy also affect the thermoregulation of the body. That is why from this moment the pregnant woman increasingly begins to feel stuffiness, weakness, frequent dizziness and changes in blood pressure.

Pregnancy by week - 12 weeks

This week marks the end of the first trimester. A lot of interesting things are happening with your baby this week. Red blood cells are already present in his blood and white blood cells are beginning to be produced - leukocytes, which in the future are responsible for protecting the body. So far they cannot protect the baby from infection. A guarantee of its safety during intrauterine life and the first months after birth is passive immunity - antibodies coming from the mother through the blood, and subsequently through breast milk.

Pregnancy by week - 13 weeks

Well, that’s all, the first trimester with all the problems and toxicosis is left behind. There is a truly golden time ahead of you, during which you can enjoy your pregnancy. Your belly is already taking on some shape, your pride in it is growing, but at the same time it is not yet difficult to wear, so you can run around an entire children’s store with great enthusiasm and a huge amount of strength.

The baby's task in the second trimester is skeletal development and growth. To do this, it requires a large amount of calcium, so you should not forget about taking special complexes for pregnant women. According to research, at this stage of pregnancy the baby begins to feel sounds with the help of special vibration receptors located on the skin. This means that now he hears and, most likely, distinguishes the sound of your voice and the voice of the future dad. His own vocal cords are still developing.

At the thirteenth week, the baby’s liver begins to produce bile, and the pancreas begins to produce insulin, and villi are formed in the intestines, which play an important role in the digestion of food.

Pregnancy by week - 14 weeks

The baby has new needs... He “learns” breathing movements - inhaling and exhaling, preparing for life outside the womb. These training movements are very important for the development of lung tissue - for that long-awaited first cry that he will make as soon as he is born. The urethra and bladder are formed, the kidneys begin to work, secreting urine. It mixes with amniotic fluid and is excreted by the placenta.

The baby's entire body gradually begins to be covered with fluff, the so-called lanugo, which performs a protective function and helps regulate the baby's body temperature. The pattern on the fingertips - fingerprints - already have a unique pattern that will remain throughout life.

M and F are increasingly different from each other. In guys, the prostate gland forms; in girls, the ovaries move to the pelvic area.

Pregnancy by week - 15 weeks

Neonatologists say that around this time the fetus begins to become aware of what is happening around it - it feels, hears and in its own way understands what is happening. He can express emotions through facial expressions and gestures. He feels his mother’s mood, their sleep and wakefulness are synchronized.

The circulatory system is improved. The first foci of hematopoiesis occur in the walls of the yolk sac. At 2-3 months of intrauterine development, the main organ of hematopoiesis is the liver, from the end of 3 - the bone marrow. From 4 months, the spleen begins to take part in hematopoiesis.

Arteries and veins provide nutrition and supply to all organs and systems: brain, heart, lungs, stomach and intestines. At the fifteenth week of pregnancy, the baby's heart beats twice as fast as the mother's. It passes through itself up to 23 liters of blood per day. If necessary, you can determine his blood type and Rh factor. This may be important when the mother is Rh- and the father is Rh+.

Pregnancy by week 16 weeks

The child learns to coordinate his actions. He moves actively - rolls, somersaults and kicks. While all these movements are not felt, the amniotic fluid softens even the most active movements of the baby.

His face is already quite well formed. At the sixteenth week of pregnancy, the baby's eyes open for the first time.
The skin of the fetus is very thin and translucent. Photographs taken using ultrasound show that the subcutaneous fat layer is still completely absent - blood vessels are visible through the skin.

My legs are getting more and more tired. Due to an increase in body weight and a shift in the center of gravity, the load on them increases. A duck gait appears, characteristic of pregnant women. You have to give up high heels and shoes with slippery soles.

The inquisitive baby is already using his hands to explore his surroundings.

The skeleton consists mainly of a flexible shaft and a network of blood vessels visible through thin skin.

Pregnancy by week 17 weeks

During pregnancy, you discover a lot of new things not only in reality, but also in your dreams. Many expectant mothers have crazy, vivid dreams. According to experts, this is due to the overstrain that your brain experiences. In addition, you get up more often at night and, thanks to this, remember more dreams than is usually possible. During the seventeenth week of pregnancy, dreams are often related to the upcoming birth or baby and can seem so real that they are constantly running through your head. Often mothers complain about nightmares - such dreams reflect the anxieties that they suppress while awake.

Research shows that babies also experience rapid eye movements during fetal life, which in adults is indicative of dreaming. In this regard, some scientists claim that babies can have dreams associated with their activity during the day. Perhaps the child dreams of stretching his legs, hearing your voice, or playing with the umbilical cord.

Pregnancy by week - 18 weeks

About 14 cm. The embryo can now perceive sounds from the outside world.

Pregnancy by week - 19 weeks

Movements. Magical feeling. In the eighteenth week of pregnancy, you constantly receive confirmation that there is someone inside.

The baby becomes large and strong enough for his movements to be noticeable to the expectant mother. First, a vibration is felt, then it seems as if butterflies are flying in the stomach, and then it becomes clearly clear that this is the child making itself felt. Within half an hour, a 5-month-old fetus can perform from 20 to 60 kicks. Their strength varies depending on the time of day, the mood and activity of the mother herself. Emotional outbursts, stuffy rooms, overexcitement, chocolate and sweets - all this makes the baby move more actively.

If you don’t feel any movement yet, it’s okay. Continue to listen to yourself and soon you will experience the joy of the “first move.”

Pregnancy by week 20 weeks

Mid-pregnancy. Equator.

You have already adapted to many of the delights of your interesting situation and are increasingly thinking about future births. Haven't chosen courses for future parents yet? It's time to think about it. Attending classes and trainings in such schools is a good prevention of complications during childbirth and psychological problems after them. You will receive information about the physiology of pregnancy and childbirth, and the features of caring for newborns. You will be able to discuss with specialists and other pregnant women issues that concern you in connection with bearing a child, relationships with relatives or raising a future heir or heiress.

This week are you interested in movements and the psychology of intrauterine development? At school you will find like-minded people and specialists who are ready to advise you on these issues.
If possible, try to attend classes with the future dad.

Your baby is already about 20 cm long. Hair is already beginning to appear on his head.

Pregnancy by week - 24 weeks

If you put your ear to your stomach at this time, you can hear the baby’s heartbeat. His rhythm is much more frequent than that of an adult - 120 - 160 beats per minute. After birth, his blood will circulate in a large and small circle. In the meantime, at this stage, placental blood circulation plays a decisive role.

Blood enriched with oxygen and nutrients in the placenta enters the body through the umbilical vein. The umbilical vein approaches the liver through the umbilical ring, then to the inferior vena cava. In it, arterial blood is mixed with venous blood, which comes from the lower part of the body and the insides of the fetus. Almost all of this blood flows through the foramen ovale (blood flow from the right atrium to the left stops immediately after birth) in the wall of the right atrium into the left atrium. From the left ventricle, blood is ejected into the systemic circulation. The upper part of the fetal body is better supplied with arterial blood compared to the lower half of the body. This explains the relatively small size of the pelvis and lower extremities of the newborn. Very little blood reaches the lungs.

Pregnancy by week - 26 weeks

At the twenty-sixth week, the baby diligently explores the space around him. For now, he still has room for active movements. He pushes, feels the umbilical cord and the surrounding walls of the uterus. According to the Pearson test, which is recommended to be carried out from the 28th week, the baby normally makes about 10 kicks per hour.

One of his favorite activities at this stage of pregnancy is thumb sucking. This strengthens the cheek and jaw muscles and calms him down. The sucking reflex is one of the first unconditioned reflexes, the so-called oral segmental automatisms. It is formed from the first trimester of pregnancy and persists during the first years of life. Preference for the thumb of the right hand, or, conversely, the left one, may be a sign of dominance of one or another hemisphere of the brain. You can already guess who the baby will be - right-handed or left-handed.

Over the past month, the uterus has increased in size 4 times. Now it rests on the hypochondrium, spreading out the lower ribs.

Pregnancy by week - 28 weeks

Lanugo (thin hair covering the entire surface of the body, with the exception of the lips, palms and soles) gradually disappears, but several “islands” may remain after childbirth - on the back, on the shoulders and even on the forehead. They will disappear in the first weeks of extrauterine life.

The hair on your head becomes thicker. Some children already at birth can boast of thick, long curls, while others have an almost bald head. Both are variants of the norm. The visible absence of hair does not mean that there is none at all.

This week the eyelids open and close. Eyelashes appeared. Toenails are growing. During this period of pregnancy, the brain mass constantly grows, the number and depth of convolutions increases. However, the functions of the cerebral cortex develop after birth. During the prenatal period, the most important functions of the fetus are regulated by the spinal cord and other parts of the central nervous system.

There are still eight to ten carefree weeks ahead, but the little man is already cramped in the uterus, and he is preparing to leave it. He turns upside down - it’s easier to get out.

Pregnancy by week - 36 weeks

This week, the expectant mother’s body can begin active preparations for the birth of the baby. Precursors appear - changes in the body that occur shortly before the birth itself.

• The nesting instinct is the internal need to prepare space for the imminent appearance of a child;
• Decrease in the height of the fundus of the uterus - or “drooping” of the abdomen;
• Discharge of the mucus plug - discharge of colorless or pinkish mucus from the cervix;
• Increased frequency of urination and defecation. The prolapsed uterus puts more pressure on the bladder and intestines. Prostaglandins, released during early contractions, can periodically signal bowel movements;
• Reducing the number of movements. The child seems to calm down and gain strength before the upcoming birth;
• Braxton-Higgs matches. Irregular, training contractions;
• Slight decrease in body weight;
• Softening and shortening of the cervix. It is possible to open the external pharynx by 1-2 cm;

Your baby's length this week is approximately 47 cm and his weight is approximately 2600 grams.

After 4 weeks the baby will see the white light. At this stage the fetus is almost full term.