Intrauterine fetus. Pregnancy and the intelligence of the unborn baby
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It is very interesting for every mother to know how her baby grows and develops, especially in the first months of pregnancy, when she still does not feel anything.- does not feel his movements, the rhythm of his day - sleep and rest, does not feel his mood.
Pregnancy will last approximately nine solar calendar months, but in obstetric practice this calculation is not accurate and therefore does not apply, we count pregnancy by weeks. Remember that each of us is individual, and your body will decide how long it will take to carry your baby. On average, a pregnancy is considered full-term at 270-290 days, or 37-42 weeks.
There are several different ways, but the simplest and most convenient is the calculation of the expected date of birth (ODD).
To calculate, you need to count 3 months ago from the first day of the last menstrual period and add 7 days. For example, on May 1 you had the first day of your last period, so the expected date of delivery is February 8 ( May 1 - 3 months = February 1 + 7 days = February 8).
In this article, we will take a detailed look at the development of the fetus by months, from conception to childbirth.
First month (0 to 4 weeks)
As I said, the first 6 days the fetus is just moving towards the uterus through the fallopian tubes.
Its cells are actively dividing along the “road”, by the 7th day it already consists of 107 cells. Approximately on the 6-7th day, the embryo reaches the uterus and stays in the uterine cavity in an unattached state for 72 hours, then it begins to actively "sprout" into its mucous membrane, this process lasts about 40 hours.
The cells of the embryo seem to grow into the uterine mucosa, put down "roots" in which blood vessels are formed, through which all the necessary substances from the mother's body will now flow. This process is called implantation.
The embryo is constantly growing, oxygen consumption increases, protein production and carbohydrate metabolism increase, therefore, in 5-7 days, the embryo exhausts all its reserves, the uterine mucosa is actively preparing to receive the long-awaited baby, making a kind of “reserve” of nutrients in the mucous cells.
A new house is ready for the baby, where he will grow and develop. 12-14 days after fertilization, the embryo is completely immersed in the decidually altered stroma of the endometrium (inner layer) of the uterus.
On day 11-12 site of implantation(attachment of the embryo) can be seen with the naked eye, it looks like a red spot 1 mm in size. From 14 to 21 days in the embryo, the stage of development of all organs and tissues begins.
During the 2nd week there is a development of mainly extra-embryonic parts of the embryo, as a life-support system for the unborn child. The cells of the germinal nodule are split into three layers and each takes the form of a disk 0.25 mm in diameter.
On the 3rd week lays the foundation for the formation of organs and tissues:
- The foundation is being laidchords, or future spine.
- The foundation of the skeletal muscles, cartilage, bones, internal organs, blood vessels, heart, blood, lymph, gonads and membranes is laid.
- The foundation is laid for the formation of the epithelium for lining the organs of the digestive and respiratory systems, the epithelium of the liver and pancreas. (Epithelium is a tissue that forms the outer integument of the body (the upper layer of the skin) and lines the internal cavities (mucous membranes) of various organs.)
- The embryo, as it were, is isolated, separated from the external parts, it has an anterior end where the head will subsequently be located, and a posterior end where the pelvis and legs will grow.
- In the third week primary yolk sac is formed. This is an extra-embryonic organ that ensures the exchange of metabolites between the mother and the fetus at those stages of its development when there is no placenta yet formed. The yolk sac is completely formed by the 32nd day of the life of the embryo, and by the end of the 6th week of pregnancy it undergoes reverse development and disappears.
So, on the 3rd week, the rudiments of all the main systems and organs of the human body appear.
Arise rudiments of the digestive system(intestinal tube and pancreas), respiratory system (rudiments of the trachea and two bronchi) and excretory system(a pre-bud is laid), begins formation of the nervous system(a wide plate is formed, from which the brain will subsequently form).
Formation of the circulatory system: the first blood vessels appear, a heart tube is formed - the future human heart.
Embryo 28 days after fertilization By week 4 the embryo still has a cylindrical shape with a large head. Now he is undergoing magical transformations, the entire path of human evolution! On some days it even resembles a fish - it has gills and a tail.
This week about another important event comes out - the heart of the fetus begins to beat, while it looks like a large swelling, like a ball on the front side of the body. The contraction of the heart can be observed from 22 days from the moment of fertilization.
All organs and systems of the future person continue to form: the rudiments of the liver, lungs, duodenum appear, the brain region grows and actively develops, eyes, mouth and ears begin to form, the rudiments of muscles form, and even the rudiments of arms and legs appear, while in the form of small kidneys on the sides of the body.
So, by the end of the first month, the prototypes of all body systems and their main organs have already been formed in the embryo. The length of the body of the embryo is 5-8 mm, and the weight is 2-3 grams.
Compare in these figures the human embryo on the left and the dolphin on the right
Second month (weeks 5 to 8)
In the second month, a huge number of changes take place, every day the embryo is filled with a mass of events, all organs, human systems develop, the tail and gills hide, and by the end of the 2nd month, the embryo looks like a future man, it has a face, eyes, eyelids, nose , arms and legs, rudiments of fingers. At the end of the second month of development, the length of the embryo is 2.5-3 cm, weight - 4-5 g.
But human and dolphin embryos are already in the 2nd month of development
Let's take a closer look at all the changes this month:
- Internal organs:
- the beginnings of the lungs are formed, the kidney is laid, the intestine is actively growing
- the liver begins to work, which takes over the function of hematopoiesis
- the heart begins to work
- the nervous system is actively developing
- ventricles form
- Skeleton and muscles:
- the face and limbs are formed
- eyes close, nose appears
- ear buds appear, teeth grains appear
- lips looming
- limbs begin to develop: first the arms (in the 5th week), and then the legs. During the second month, the arms and legs grow so actively that different sections of the legs and arms have time to form: the shoulder, forearm, hand, and even the rudiments of fingers and toes.
- muscles begin to contract
- Nervous system:
- the nervous system and the brain are actively developing, in the second month all layers of the cerebral cortex are formed
- on the 7th week for the first time you can fix brain impulses
Third month (from 9th to 12th week)
The third month of pregnancy is very important for the development of the child, it grows at a very fast pace, its face is constantly changing, the features are becoming more and more distinct.
By the end of the third month baby starts to move, you will not feel him yet, since he is still very tiny, his movements are very gentle and delicate, but he already knows how to frown and squint, tries to suck his finger and clench his fist.
His heart is actively working, making 130-150 beats per minute.
The intestines begin to work, because your baby is already learning to swallow amniotic fluid.
By the end of the third month the length of the fetus is 7-9 cm, weight - 15-25 g, that is, it increases almost 5 times in 1 month! Starting from the third month, it is no longer called the embryo and is already called the fetus! He's already a little man!
10 weeks Let's see the main changes of the third month:
- the liver develops continuing to perform the function of the main organ of hematopoiesis. The blood of the fetus is not yet similar to the blood of an adult, at the 6th week, red blood cells appear in the blood(erythrocytes),at 12-16 weeks - white blood cells(leukocytes).The hemoglobin content is still very low and it will increase only by the time of delivery.
- the skeleton continues to form, rudiments of nails appear on the fingers, “fingerprints” appear on the handles.
- muscles begin to work, allowing the baby to move: he can already move his arms, legs, turn his head, open his mouth. At the twelfth week he makes his first attempts to suck and swallow.
- elongates and twists into loops of the intestine the process of digestion begins.
- at the end of the third month of pregnancy external genitalia begin to form.
- the placenta is almost completely formed. Up to 12 weeks of pregnancy, the baby is most vulnerable to harmful factors - smoking, alcohol, stress, infections, since the placenta is not yet formed and cannot protect the baby.
This is what a baby looks like at 12 weeks
The role of the placenta, amniotic sac and umbilical cord
Placenta(children's place) is the most important organ, thanks to it our embryo feeds, breathes, it removes all waste products, takes on the functions of the lungs, digestive organs, kidneys, and skin.
After 16 weeks (the first 16 weeks, the placenta is only being formed along with the growth of the child, at which time the mother's glands produce all the hormones for two), the placenta also becomes a gland, which produces all the hormones the baby needs.
In addition, she protects the baby from many harmful substances, pathogenic microbes, toxins, from the effects of certain drugs that the mother takes, but the placenta can not cope with alcohol and nicotine. If a mother smokes or drinks, then nicotine and alcohol immediately and directly get to the child.
The placenta is similar to a soft thick cake, closer to childbirth its diameter reaches 15-18 cm, thickness - 2-3 cm, weight - 500-600 g.
According to the placenta, the doctor can tell the whole story of the intrauterine life of the baby. It's like a kind of passport.
amniotic sac- this is essentially a "bag" in which the fetus is located, surrounded by amniotic fluid.
Aquatic baby habitat! It is very important that the baby is actively moving! Amniotic fluid is also a very important component of the successful development of the baby.
Umbilical cord connects the baby's body to the placenta.
Through her blood vessels- two arteries and one vein - blood flows from fetus to placenta and back passing through the placenta, the blood is released from carbon dioxide and saturated with oxygen, which again enters the child, this is the new one, the third circle of blood circulation in your body.
In appearance, the umbilical cord resembles a cord or rope, it grows with the child, constantly increasing in size, and by childbirth the length of the umbilical cord reaches 50-60 cm, and the diameter is about 1.5 cm.
The first three months are a very important time for you and your baby..
He goes through a lot of transformations, changes completely in a matter of days, the foundation of all his organs and systems is laid. After three months, he begins to clearly feel you, even react to your mood, sounds, touches - with movement.
Your body is also undergoing quite strong changes, and they concern not only physiology, but also the psyche.
The most important thing during a change of mood, a change in well-being, morning sickness, remember that your baby is developing very actively now - he is growing, and unknown transformations are taking place in your body, and all the inconveniences are happening for a reason, but for a great goal - the birth of a Baby!
Imagine him so small, fragile and so in need of your love and all difficulties will be easily overcome. Only positive emotions, the realization that you are involved in the great mystery of the birth of a new life, will make you truly happy at this crucial moment, and your pregnancy a joyful event.
Second trimester
In the second trimester, nausea, malaise, strange reactions to smells and food are behind, ahead is the golden time of pregnancy - the second trimester.
By the 16th week of the second trimester the placenta is fully formed, but, starting from the 12th week, she takes over the function of hormone production. Until that time, this function was performed by the corpus luteum of pregnancy, it was it that caused all the "troubles" and torments.
Women rightly call the second trimester the most enjoyable time in their entire pregnancy - a woman is already getting used to her new position, a riot of hormones and major changes in the body are behind her, her stomach is still small and does not bother at all.
It is in the second trimester you can feel an incomparable happiness - a feeling of the coming Motherhood!
Many women describe these feelings as a deep satisfaction with everything that happens, a sense of predestination and the highest meaning of their being. All the problems at home, at work, in the world seem quite insignificant. A woman knows why she came into this world, and feels that she is fulfilling her most important task.
The future mother is at the peak of her femininity and creativity– at this time there is a real chance to create something infinitely beautiful and talented. You may feel the urge to start writing poetry, paintings, singing, playing different instruments - don't stop yourself - just go ahead!
The baby also went through one of the most difficult stages- the period of laying the most important organs and systems, in other words, from a pea in the first three months he turned into a little man.
Ahead of him awaits: explosive growth- in the next three months, he will grow from 7 centimeters to 30, his weight will increase 20 times - from 15 grams to 300.
In the second trimester he starts moving and you will finally begin to feel his movements, he will begin to dream and he will even have his own daily routine. He will begin to hear you and react to light and sounds. You can start reading fairy tales to him, singing songs to him, talking to him.
Now let's look at the conquests of each month in detail:
4th month: 13-16 weeks
In the fourth month, the baby grows very quickly.- growing by 3-8 centimeters in length (by the end of the fourth month - 12-17 cm) and increases in weight almost ten times from 25 grams in the third month to 200 grams.
The most important achievement of this month is movement!
The fetus begins to reflexively move, it makes not only simple movements - it moves its head, arms, legs, but also complex ones - it finds its mouth with a fist, begins to suck a finger, finds the umbilical cord with its hands. Women who give birth not for the first time can feel his movements, they are very weak and barely perceptible, but they can be caught.
The entire digestive system begins to work.
The child has the first taste sensations, he reacts to those substances that are dissolved in the amniotic fluid - to sweet - by active swallowing, to bitter and sour - the most minimal. It is this swallowing that gives training to the entire digestive system. The excretory system is actively working, urine is excreted through the placenta into the mother's blood.
The baby switches from the mother's hormones to his own and placental hormones.
And from this month, she can even share hormones with her mother. Hormones play an amazingly important role, it is due to them that the child grows and develops, the more and better the fetus is supplied with hormones, the better and faster it grows.
This month a child's blood contains all the cells of an adult and it is already possible to determine his blood type and her Rh factor.
By week 16, the external genitalia are formed, and you can find out the sex of your unborn baby, of course, if he turns right during the ultrasound.
Digestive system
- The liver becomes the digestive organ
- The stomach, intestines, gallbladder begins to work
- Taste sensations appear
- Formed primordial feces - "meconium"
The excretory system begins to work
- The kidneys begin to excrete urine
The placenta is finally formed
Hormonal system (endocrine)
- The adrenal glands and thymus begin to work
Blood
- The bone marrow takes over the role of hematopoiesis from the liver
Brain
- Brain cells are actively dividing, furrows and convolutions appear
Heart
- The heart beats very actively, now it can be heard even with a simple stethoscope
Leather
- The baby's skin remains very transparent and thin, because there is no adipose tissue under it yet, all the vessels are visible through it and therefore it seems red.
5th month: 17-20 weeks
The most important achievement of this month is active stirring, now even mothers, pregnant women for the first time will not confuse the baby’s movements with some kind of “gas” inside, now these are active jolts 4-8 times per hour.
amazing all components of the fetus's own endocrine (hormonal) system develop quickly and fully, providing him with a stable and rapid growth and development of all organs and parts of the body. It almost doubles in size this month. the length of the fetus by the end of the fifth month is 25-27 cm (in the 4th month only 12-17), weight 300 grams.
During the fifth month, the baby getting prettier and prettier, subcutaneous tissue develops and the skin becomes less red, vellus hair appears on the body and almost the entire body is covered with a cheese-like lubricant - it helps protect the baby from exposure to harmful organisms and mechanical damage.
The baby's eyes are still closed, but he is already perfectly oriented in the uterus if you have twins or twins, they can already find each other and hold hands.
A facial expression appears on his face - now he can frown, smile, be sad!
5th Month Changes
Leather
- Subcutaneous tissue develops, skin still appears red and wrinkled
- The body is covered with cheese-like grease and vellus hair
Lungs begin to form
Endocrine system
- Almost all systems are formed: pituitary, epiphysis, adrenal glands, pancreas, thyroid and parathyroid glands
The formation of all parts of the heart is completed
There is a laying of molars and milk teeth
Facial expression appears
6th month: 21-24 weeks
During the sixth month, the baby becomes very beautiful - adipose tissue is already formed under the skin and the skin does not look red, the arms and legs become more rounded.
The face is already formed - the eyes, the nose stands out, the ears increase and finally take shape, eyebrows and eyelashes appear.
baby this month moves very actively, he has his own daily routine He sleeps and stays awake at certain times. You can watch him and remember the hours of rest and activity, most likely they will continue after birth, this will give you the advantage of at least some time planning in the first months.
He distinctly Responds to loud noises and bright lights- can quiet down and hide, as it were, or, on the contrary, begin to move violently - move arms, legs, head. Keep this in mind and try not to expose your child to either.
The best sound for him now is the happy, gentle voice of his mother.
The baby begins to train his breathing- he takes 50-60 breaths per minute, then calms down for half an hour or an hour. Then it starts again. During this “breathing”, amniotic fluid enters the lungs, but it does no harm and is quickly absorbed into the lungs.
During the sixth month, the baby is fully formed, but it is not yet ready for birth, since the placenta does not yet have the necessary antibodies that can protect the baby in the first days after birth.
6th month changes
Leather
- Subcutaneous fat appears
- The whole body is covered with vellus hair and grease
Face
- Well formed eyes, eyelashes and eyebrows appear
- Take the final shape of the nose and ears
- The main tissue of the molars (dentin) is finally formed
Brain
- The brain grows very actively, the weight of the brain by the end of the 5th month is 20-25 grams, and by the end of the 6th - 100 grams
Lungs
- The child makes constant training breaths - 50-60 per minute
- Ends formation of the digestive and hematopoietic systems
Traffic
- The baby is moving very vigorously while still floating freely in the amniotic fluid.
There is a mode of sleep and wakefulness, sleep takes an average of 16-20 hours.
There is a reaction to bright light and a sharp sound
At the end of the second trimester, the expectant mother enters the home stretch. Ahead only childbirth and happy years of motherhood. There will be no such major changes, every next month the child will be more and more prepared for the birth: gain weight (at 9 months the child weighs more than 3 kilograms), his own heat regulation system will be formed, which will not allow him to freeze when he is born. into the light, the lungs will finally develop to allow the baby to easily switch to a new type of breathing.
third trimester
The third trimester is the time when a woman ceases to be afraid and begins to wait for childbirth.
The child is growing rapidly, every day he weighs more and more. By 8-9 months, the uterus greatly increases in size and presses on the diaphragm, making it difficult to breathe; presses on the stomach, causing heartburn; in the supine position, it can compress large veins, through which blood flows from the bottom up, from the legs to the heart.
A woman clearly feels her child, as he occupies all the space in the uterus and it becomes cramped. Therefore, pushes with arms or legs become very sensitive.
The breast begins to prepare for lactation (feeding child) there may be a slight discharge of colostrum.
Now all the changes in the child are aimed at preparing for childbirth and life outside the womb. All organs and systems grow and form: lungs are formed so that the child can take his first breath; subcutaneous fat grows so that the baby can retain heat well when it is born; the organs of the endocrine system are constantly developing in order to release all the necessary hormones at the right time, allowing the child to actively participate in the process of childbirth, adrenaline and norepinephrine.
Let's see what and how develops every month.
7th month: 24-28 weeks
By the end of this month, the baby is so mature that he is already viable even with an early birth, but he will need professional medical care.
The most important thing that will allow him to adapt to a new environment and survive is the growth and formation of lungs and special substance - surfactant, which month after month covers the entire surface of the alveoli. This substance prevents the lungs from collapsing when inhaled. At the 7th month, there is still quite a bit of it, which is why a child born at this time will need help in breathing.
Also in this period very little so-called gray fat which provides heat retention. Therefore, babies born in this period are very sensitive to low temperatures, cooling for more than 5 minutes can cause very serious illnesses in the baby, which is taken into account when caring for premature babies.
Baby's eyes open this month, the pupillary membrane falls, and during wakefulness he "floats" in the amniotic fluid with open eyes. The nervous system and brain are developing very actively, which makes it possible to distinguish and even remember what they saw, heard, felt or tasted: the taste of amniotic fluid, light, external and internal sounds.
Subcutaneous adipose tissue develops, the skin begins to gradually smooth out, the arms and legs become rounded. The nails do not yet reach the fingertips, the cartilages of the nose and ears are soft.
The baby can actively move in the uterus, since it does not yet occupy all of its space, by the end of the month it will reach 35 cm in length, and 1 kg-1.2 kg in weight.
7th Month Changes
Lungs:
- Active formation of alveoli and alveolar ducts
- Surfactant is produced
Endocrine system:
- All organs of the endocrine system are actively developing, now they are able to produce even growth hormone
Brain:
- The brain and nervous system are actively developing, allowing the child to differentiate different information coming from the senses
- The bone marrow gradually becomes the main organ of hematopoiesis
8th month: 29-32 weeks
Every day, the child is more and more prepared for the upcoming life outside the mother's body and childbirth. It already weighs about 1.5-1.6 kilograms and reaches a length of 40 centimeters. Now he occupies almost the entire place in the uterus, so his movements are very rational. He no longer “floats”, but makes more precise movements with his arms and legs.
During the 8th month the baby takes the position in which he will be in childbirth.
In 96% of cases it is head presentation.- that is, the child is located strictly head down, there is also a breech presentation- when he takes a position with his ass or legs to the exit from the small pelvis, as well as transverse presentation- when it lies across the longitudinal axis of the uterus.
The best for natural childbirth, of course, is the cephalic presentation, but at the 8th month, the baby's presentation can still change on its own or with the help of special exercises. However, if he is already settled (head presentation), you can wear a bandage to secure this position.
Your doctor, using special palpation techniques - Leopold's maneuvers, can very easily determine the position of the fetus.
On the 8th month alveoli continue to form, the amount of surfactant increases.
The heart and circulatory system are almost completely formed: between the right and left atrium while there is a hole ( batallov duct ), so mixed blood flows in the veins and arteries of the child. This opening will close after birth.
8th Month Changes
- Growing head, reaching a size equal to 60% of the head of an adult
- Alveoli and surfactant are formed
- Liver lobules form improves blood supply to all liver cells
- The pancreas begins to work supplying the blood with insulin
- Excellent the excretory system works Every day, the baby excretes half a liter of urine into the amniotic fluid.
- Ability to focus eyes in all directions
9th month: 33-36 weeks
9th month is usually time of birth of the child, birth after 36 weeks, is considered physiological and natural, the child is completely ready for birth.
Lungs fully developed, the entire space of the alveoli is covered with surfactant.
Significantly grown the layer of subcutaneous fatty tissue is already able to regulate heat transfer newborn and will not let him freeze. The skin straightens, acquires a pleasant pink color, vellus hair disappears from the body, remains only on the head, where it becomes thicker and longer, the nails grow so much that they begin to protrude beyond the fingertips.
Liver and pancreas continue to develop, but their development will continue for several years after birth.
The activity of the child is now minimal, since he is very crowded in the uterus, because his weight doubles this month - from 1.5 kg to 3.0.
All systems of the child are functioning normally, but the process of their improvement and improvement is still going on.
10th month: 37-40 weeks
Do not worry if the baby is not born in the 9th month, he still has time. Birth at 37-42 weeks is completely natural and normal. You must trust in this child and your wise organism, they themselves will select the best time.
So, at the 10th month, all the baby's systems are ready for birth. The digestive tract works: intestinal villi move the original feces down to the large intestine, the stomach works, the pancreas produces pepsin, which is necessary in digestion.
However, the digestive system of a baby in the womb is completely sterile., all the necessary bacteria that help digest and assimilate food will appear only during lactation from the mother's breast milk.
Completes development of the reproductive system- in girls, the large labia close the small ones; in boys, the testicles in most cases descend into the scrotum.
The adrenal glands increase in size so much that they become larger than the kidneys, since they account for the production of stress hormones during childbirth - adrenaline and norepinephrine.
Skull bones and sutures remain soft and supple. 2 fontanelles - parietal and occipital help the skull to take a comfortable shape in order to pass through the mother's birth canals without injury.
What symptoms are more common at each stage of pregnancy? How does the fetus develop?
It is normal for these issues to arise during pregnancy. A woman should know in advance what symptoms will appear at different stages. Pregnancy can be different from woman to woman. Even for the same mother from one pregnancy to another.
A typical pregnancy usually lasts about 40 weeks, counting from the first day of a woman's last menstrual cycle, which is about two weeks before conception.
Pregnancy is divided into three trimesters. Each of these periods lasts from 12 to 13 weeks.
Stages of embryo development during 38 weeks During each trimester, changes occur in the pregnant woman's body as well as in the developing fetus, and a summary of these stages will be described below.
Conception and implantation
About two weeks after a woman has had her period, she ovulates and her ovaries release one mature egg. The egg can be fertilized within 12-24 hours of its release as it travels down the fallopian tube towards the uterus.
If an egg meets a sperm cell that has made its way into the fallopian tube, it combines into one cell, a process known as fertilization or conception.
At fertilization, the sex of the fetus is already determined, depending on whether the egg receives an X or Y chromosome from sperm. If the egg receives an X chromosome, the baby will be a girl; The Y chromosome means that the child will be a boy.
According to the Cleveland Clinic, it takes about three to four days for a fertilized egg (or embryo) to travel to the lining of the uterus, where it attaches or implants to the wall of the uterus. After implantation of the embryo, the cells begin to grow. It eventually becomes a fetus and a placenta, which is tissue. This tissue can transport oxygen, nutrients, and hormones from the mother's blood to the developing fetus throughout pregnancy.
First trimester (weeks 1-12)
A woman will have many symptoms during her first trimester as she adjusts to the hormonal changes of pregnancy. In the first weeks of pregnancy, the pregnancy may not show on the outside of her body, but inside, many changes take place.
For example, human chorionic gonadotropin (hCG) is a hormone that will be present in a woman's blood from conception. HCG levels can be detected in a woman's urine about a week after a missed cycle. That is why a woman will have a positive result on a home pregnancy test.
Other hormonal changes can contribute to pregnancy symptoms: Rising levels of estrogen and hCG can cause nausea and vomiting, known as morning sickness, that a woman usually experiences during the first months of pregnancy. Despite its name, morning sickness can occur at any time of the day.
The woman will also feel more tired than usual. This is due to increased levels of the hormone progesterone, which increases drowsiness. She may also need to urinate more frequently as her uterus grows and presses on her bladder.
Early in pregnancy, a woman's breasts will feel more tender and swollen, which is another side effect of increased pregnancy hormone levels. Her areolas, the skin around each nipple, will darken and enlarge.
A pregnant woman's digestive system may slow down to increase the absorption of beneficial nutrients. But decreased mobility of the digestive system can also cause common complaints such as heartburn, constipation, bloating, and gas.
As more blood circulates to a woman's face, she will give her skin a more pink color, described as the "glow of pregnancy."
In addition to the physical changes in a woman's body, she may also experience emotional highs and lows in the early months of pregnancy and throughout. These emotions can range from smoldering, mood swings, and forgetfulness to fear, anxiety, and excitement.
Development of embryos/fetus of the first trimester
A developing baby is called an embryo from conception, which occurs before the eighth week of pregnancy.
According to the American College of Obstetricians and Gynecologists (ACOG), during the first month of pregnancy, the heart and lungs, arms, legs, brain, spinal cord, and nerves begin to develop.
The embryo will be the size of a pea for about a month. In the second month of pregnancy, the embryo will grow to the size of a bean. In addition, ankles, wrists, fingers and eyelids appear, bones appear, genitals and the inner ear appear.
After the eighth week of pregnancy and before the baby is born, the developing baby is called a fetus.
By the end of the second month, eight to ten major organs of the fetus have formed. During this stage of pregnancy, it is extremely important that pregnant women do not take harmful medications such as illegal drugs. The first trimester is also the period when most miscarriages and birth defects occur.
During the third month of pregnancy, bones and muscles begin to grow, buds for future teeth appear, and fingers and toes grow. The intestines begin to form, and the skin is almost transparent.
Second trimester (weeks 13-27)
By the second trimester, some of the unpleasant effects of early pregnancy may lessen or disappear as a woman's body adjusts to its changing hormone levels. Sleep may become easier and energy levels may increase.
Nausea and vomiting usually improve and go away. But other symptoms may occur as the fetus continues to grow and develop.
A more visible baby appears when the uterus grows behind the woman's pelvis, and the skin on her expanding belly can look like stretch marks.
As the fetus gets bigger and the woman gains more weight, she may also experience lower back pain.
Between the 16th and 18th weeks of pregnancy, the mother may feel the first fluttering movements of the fetus. If a woman has had a baby before, she is more likely to feel the fetus kicking, squirming or turning even sooner because she knows what to expect.
The 20th week usually marks half of a woman's pregnancy.
Embryo / fetus development in the second trimester
In the second trimester, the fetus grows faster and will be 3 to 5 inches long. Between 18 and 22 weeks, an ultrasound can reveal the sex of the baby if parents want to know this information ahead of time.
By the fourth month of pregnancy, eyebrows, eyelashes, nails and neck are formed, and the skin has a wrinkled appearance. In addition, during the fourth month, the arms and legs may bend. The kidneys begin to work and can produce urine, and the fetus can hear.
In the fifth month of pregnancy, the fetus is more active, and the woman can feel her movements. The fetus also sleeps and wakes up in regular cycles. Fine hair (called lanugo) and a waxy coating (called vernix) coat and protect the delicate skin of the fetus.
By the sixth month of pregnancy, hair begins to grow, eyes begin to open, and the brain develops rapidly. Although the lungs are fully formed, they are not yet functional.
Stages of pregnancy for nine months. Third trimester (weeks 28-40)
In the third trimester, when a woman's enlarged uterus pushes up her diaphragm. The main muscle involved in breathing can become short of breath because the lungs have less room to expand. Her ankles, hands, feet, and face may swell as she retains more fluid and circulation slows.
The mother will have to urinate more often because there will be more pressure on her bladder. She may also have more back pain and pain in her hips and pelvis as these joints relax in preparation for childbirth.
Dark spots may develop on her face, and stretch marks may appear on her abdomen, thighs, chest, and back. She may also notice varicose veins in her legs.
In the third trimester, women's breasts may experience some leakage of colostrum, a yellow liquid, as they prepare to breastfeed. The baby will sink down into the belly.
During the last weeks of pregnancy, it becomes more difficult to find a comfortable sleeping position, so women can be very tired.
As labor approaches, some women enjoy the experience of being pregnant, while others may feel like they can't wait for it to be over.
Embryo / fetus development in the third trimester
By the seventh month of pregnancy, the fetus hits and stretches, and can even respond to light and sound and music. Eyes can open and close.
During the eighth month of pregnancy, the fetus gains weight very quickly. The bones harden, but the skull remains soft and flexible to facilitate childbirth. According to ACOG, different areas of the brain are being formed and the fetus is capable of hiccups.
The lungs are now fully mature to prepare to function on their own. The fetus continues to gain weight rapidly.
The new definition of an extended pregnancy is when a baby is born after 39-40 weeks.
A woman was created by nature in such a way that at least once in her life she can give the world a new person. The period of expectation and the birth of a child is the brightest and at the same time disturbing time. But the expectant mother should not worry in vain. She should know that a normal pregnancy is the key to the proper development of her child.
If a woman has a clear idea of how the baby’s body is formed throughout pregnancy, then it will be quite easy for her to do everything necessary in order to avoid the development of pathologies.
Should a woman know how her child develops?
Knowing how the intrauterine development of the fetus occurs by weeks, the expectant mother can correctly organize her diet and daily routine. Also, the presence of complete information about what changes are considered the norm, a woman will avoid a state of unreasonable anxiety.
Calculating the intrauterine development of the fetus by weeks, it should be noted that it lasts 40 of these calendar periods. In other words, a woman's pregnancy lasts 280 days. During this time, the child undergoes a complete process of formation and development of all organs and systems.
Gynecologists consider the intrauterine development of the fetus by weeks and by periods, which are distinguished by two: embryonic and fetal.
The first lasts from the moment of fertilization of the egg until the 8th week of pregnancy. During this period, after fertilization, an embryo is formed, which descends into the cavity and attaches to it. The fetal period lasts from the beginning of the 9th week until the moment of delivery. The embryo transforms into a fetus, develops and grows.
It is also common to divide pregnancy into trimesters:
- First trimester (1 - 12 weeks).
- Second trimester (13 - 27 weeks).
- Third trimester (28 - 40 weeks).
Now you can consider in more detail how the intrauterine development of the fetus occurs by week.
What happens during the embryonic period?
The most important of this period of development is the formation of the embryo. Over time, it begins to take on the shape of a person. The embryo is formed from the moment the egg is fertilized. It usually occurs in the fallopian tube.
From the moment of fertilization of the egg, the development of the fetus begins.
By weeks of pregnancy, a morula is formed in the first seven days. It is a multicellular organism, a prototype of the embryo. The morula attaches itself to the wall of the uterus, and its outer cells form the umbilical cord and outer membranes of the fetus. From the cells that are located inside it, the organs and tissues of the unborn child are formed.
What does a woman feel?
In the first week of pregnancy, a woman's body temperature is slightly elevated, it is close to 37 ° C. There are no hormonal changes in the body yet, but the expectant mother instinctively feels the changes taking place. From this moment on, a woman should be very careful about her diet and lifestyle, eliminate bad habits and follow the doctor's recommendations.
Every expectant mother will be very interested in how the fetus develops by week of pregnancy. This information will help a woman prevent many dangerous conditions. The third week of pregnancy is alarming because it is during this period that there is the greatest risk of fetal rejection. The immune system of the woman's body tries to reject the embryo. However, in response, a special protein is released that suppresses this protective reaction, and the unborn child has a great chance of survival.
What happens to the embryo in the first weeks of pregnancy?
This period is also characterized by the formation of the placenta. An unborn child at three weeks is a ball with a diameter of 0.2 mm. But during this period, the lungs and respiratory organs, the cardiovascular system, the spinal cord and brain are actively formed, as well as the face and gender of the baby.
A woman begins to feel mood swings, drowsiness and fatigue, early toxicosis may occur.
Further development of the fetus (this is the fourth week of pregnancy) is very intensive. In the unborn child, three germ layers are formed:
- endoderm - the basis for the development of internal organs;
- mesoderm - that from which the skeleton and bones will be formed;
- ectoderm - material for the formation of the nervous system.
The embryo already has a pulsating tube that develops into a heart. On ultrasound during this period, a heartbeat is heard. The respiratory organs, the brain continue to form, the face is more clearly looming. The embryo develops limbs, and by the end of the week they are already bent. The fetus is located in the placenta and maintains contact with the mother through this organ.
His heart is already beating!
During this period, many women only find out about their pregnancy, especially if it is the first. Having found out this fact for herself, the future mother is interested in the main question: how does the development of the fetus occur?
By weeks of pregnancy, this is the fifth calendar period. At this time, the embryo still bears little resemblance to a person, but its heart is already beating, the sex is clearly defined, the kidneys, liver, pancreas and thyroid glands are being formed.
Already at the 8th week, the future baby takes on the shape of a person, his height is 3-4 cm. He has already formed arms and legs, his forehead is clearly visible, the outlines of the eyes, lips and nose have been outlined. Internal organs are actively formed and developed. The stomach is already able to produce juice, the heart is formed, the intestines are growing, the trachea and bronchi have appeared. The spine, brain and limbs are actively developing.
By the end of the eighth week of pregnancy, the embryonic period of development ends, but the first trimester is still ongoing. The unborn child has already acquired a human appearance, the placental-uterine circulation has been formed.
fetal period
This stage begins from the 9th week of pregnancy and lasts until the very birth. The fetal period is divided into two parts:
- early (9 - 28 weeks);
- late (29 - 40 weeks).
In the early fetal stage, the development of the fetus continues. By weeks of pregnancy - this is the ninth. At this time, the growth of the fetus is 40-50 mm. He begins to show activity: he bends his arms and legs, turns his head, brings his fingers to his mouth. But the mother is not yet able to feel it, the fetus is still too small.
Outwardly, the future baby looks like a little man with a big head. The eyes are still closed, and the skin is transparent. The sexual organs begin to form, and this process will continue until the 20th week. The cerebellum and pituitary gland develop. The heart has four chambers. The tail disappears, being replaced by the coccyx.
Embryo turns into a fetus
At the tenth week of pregnancy, the embryo is already called a fetus, and weighs 5 grams. In his photographs, isolated fingers, neck, elbows, knees, eyelids and upper lip are already visible.
There are taste buds on the tongue, the thickness of the umbilical cord increases.
The eleventh week of pregnancy is characterized by the further development of the fetus. He already has eyelashes and milk teeth. The rectum is formed. The spinal cord is already producing red blood cells. The intestines are ready to go.
Many mothers during this period are sent by a gynecologist for a planned ultrasound. Going through this procedure, women are interested in the main question: is the development of the fetus normal?
By weeks of pregnancy, the twelfth period begins. During this period, the phalanges of the fingers and earlobes are formed in the child, he opens and closes his eyes. The intestines are already contracting, and the liver is able to secrete bile. The baby's circulatory system functions, leukocytes appear.
At the twelfth week, the first trimester of pregnancy ends and the second begins.
Baby is actively growing
During this period, all fetal systems are formed, their development and growth is underway. At the thirteenth week, which marks the beginning of the second trimester, the baby reaches up to 80 mm in length and weighs about 20 g. At this time, the skeleton is intensively formed in the fetus, the pancreas begins to produce insulin.
The gynecologist will refer the expectant mother for the first genetic study. After examining the results of the ultrasound, the doctor will be able to tell you how the intrauterine development of the fetus occurs by weeks of pregnancy, whether the indicators correspond to the norm.
At the 14th week, the baby's face continues to form, facial expressions, eyebrows and hair on the head appear. On the body of the fetus, a fluff and a cheese-like lubricant are formed. The thyroid gland begins to work, its own hormonal background develops.
The excretory system functions, the child makes respiratory movements.
In the antenatal clinic, you probably saw a stand that shows the intrauterine development of the fetus by weeks.
A table with this kind of information will be useful to every woman.
At the fifteenth week of pregnancy, the baby develops hearing, the intestines form the original feces, the placenta thickens. The fruit weighs about 50 g, its height is 60 mm.
Expectant mother feels the first movements of the baby
The sixteenth week of pregnancy is marked by an increase in the volume of amniotic fluid. The child is actively moving, and the mother begins to feel it. Muscles are developed on the face and facial expressions are characteristic of the child at this time. Bones and nails are already almost fully formed, the skin is very thin and blood vessels are clearly visible through it.
During this period, the gynecologist sends the woman for a second genetic screening. For this, the expectant mother will have to undergo a second ultrasound. It perfectly shows the intrauterine development of the fetus by weeks. Photos that can be taken at this stage are presented below.
Counting fetal movements
From the 28th week of pregnancy, the third trimester begins, and from the 29th - the late fetal period. At this time, the child is cramped in the womb, and his movements are not so active. Nevertheless, a woman must clearly track the tremors, their number should be at least 10 per hour. The brain is actively developing, and furrows appear on it. The teeth are covered with enamel, the eyes are capable of focusing. The weight of the baby is about 1250 g, and the height is 37 cm.
At the 30th - 31st week of pregnancy, the baby is already in its final position in the uterus. The fetus is actively gaining weight through an increase in muscle mass and subcutaneous fat. If a child is born during this period, he has every chance of survival.
Further intrauterine development of the child (by weeks this is already the 32nd calendar period) is characterized by the improvement of the immune and nervous systems. The child has his own schedule of wakefulness and sleep, he has his own temperament. The baby weighs 1800 g, and its height is 42 cm.
At the 33rd - 34th week of pregnancy, the baby actively trains the lungs, perceives the entire environment in full. The skin of the fetus becomes smooth, the bones of the skull become stronger.
Baby is preparing for birth
At 36-37 weeks of gestation, the fetus is preparing for birth. In the mother's stomach, he is already cramped and it is becoming more and more difficult for him to move.
In his body, there are enough fat reserves for thermoregulation after birth, the lungs are ready for breathing. The fluff on the body is no longer there, but the hair on the head and nails grow.
On the 38th - 40th week, all mothers expect childbirth. This can happen at any time. The child descends and the mother becomes easier to breathe. A woman carefully monitors the discharge of the mucous plug and the appearance of contractions.
And finally, it worked out! Mom and baby are together now. The baby is still very small, but full of energy to explore the new world. Now his status is a newborn.
Table of intrauterine development of the fetus by week of pregnancy
This article gives a full description of how the intrauterine development of a child takes place by week. The table below will serve as a kind of conclusion to all of the above and will serve as a reminder for the expectant mother.
| gestational age in weeks | Fruit length, cm | Fruit weight, g | Development of organs and systems |
| 4 | 0,1 | Fertilization of the egg, its implantation, embryo and organ rudiments. | |
| 5 | 0,15 - 0,2 | Bookmark of the liver, pancreas, upper respiratory organs, heart. | |
| 6 | 0,4 - 0,6 | The appearance of the rudiments of limbs, listening to the heartbeat, the neural tube closes, parts of the larynx and middle ear are formed. | |
| 7 | 0,7 - 0,9 | The trachea, esophagus, small intestine, adrenal glands and sternum develop. The brain is active. | |
| 8 | 0,9 - 1,2 | The embryo clearly distinguishes the body and head, which are equivalent in size. The rudiments of the nose, eyes, mouth and organs of the reproductive system are formed. | |
| 9 | 1,3 - 1,5 | 1 | The cerebellum develops, fingers form on the limbs. |
| 10 - 11 | 2,7 - 3,5 | 4 | Joints, upper lip, auricles, external genitalia, rudiments of milk teeth develop. |
| 12 | 9 | 20 - 25 | The face is being formed, the intestines are contracting, the liver is producing bile, the child is moving. |
| 13 | 10 | 28 | Limbs are fully formed. The pancreas produces insulin. |
| 14 - 15 | 12,5 | 50 - 90 | The excretory system is active, the child produces urine. |
| 16 | 16 | 120 | Distinguish the gender of the fetus. The skin is very thin, muscles are formed. The child does not move so chaotically, the mother feels the first shocks. |
| 20 | 25 | 280 - 300 | On the skin of the baby there is a fluff and a cheese-like lubricant. The intestines form the original feces. The child is able to hear. |
| 24 | 30 | 600 - 800 | The work of the kidneys is activated, the fetus is dynamically gaining weight. |
| 28 | 35 | 1200 | The muscles and reproductive system of the child are being formed. |
| 32 | 40 | 1500 - 1600 | There is an active development of the senses and the nervous system: the baby is able to see the light and feel the taste. |
| 36 | 45 | 2400 - 2500 | The child quickly gains weight, his activity decreases. |
| 40 | 50-52 | 3200 - 3500 | The baby is ready to be born. |
Of course, it is best to study this information when pregnancy is just planned. Then the woman is more likely to properly organize nutrition, regimen, intake of necessary vitamins and minerals. However, information about the intrauterine development of the baby will always be timely and interesting for the expectant mother, regardless of the duration of her pregnancy.
When planning a pregnancy, few people think how important it is to have information about a particular period of a pregnant woman's life. Couples planning to conceive need to know how the fetus is formed in the first days of its life in order, for example, to plan the sex of the child or understand the need to prepare for gestation. We will try to consider in more detail the development of the embryo by day from conception to the end of the first trimester.
The development of the embryo from conception to birth is a rather difficult period, the well-being of which is determined by the first days of intrauterine life. Fertilization plays a big role in determining the sex of the baby, and the subsequent stage at which the tissues and organs of the child are formed determines the success of the development of the fetus.
Any pregnancy begins in the middle of the menstrual cycle, namely from the moment of fertilization of the egg, although in obstetrics it is customary to consider the first day after menstruation as the beginning of pregnancy. Conception occurs on the day of ovulation, since the ability of the egg to procreate is lost 12-24 hours after the rupture of the follicle.
In the fallopian tube, after penetration of the sperm into the egg, a diploid cell is formed, which begins to divide exponentially. On the 4th day after conception, there are 58 divided cells in the zygote, 53 of which will become the basis for the formation of tissues and internal organs of the child, and the other 5 will take part in the formation of the placenta, amniotic bladder and umbilical cord.
On day 5, the zygote passes into the blastocyst stage, which is characterized by the presence of a vesicle with liquid and subsequent resorption of the zygote membrane. At this stage, the fetus begins to gain weight. At 7-10 days after conception, the implantation of the embryo into the uterus begins.
Attachment of the embryo to the uterus - the moment of truth
From conception to implantation, depending on various factors, 7-10 days pass. The beginning of implantation takes place by the end of the week after conception, when the embryo, moving through the fallopian tubes, reaches the uterine cavity. Depending on the condition of the endometrium, its thickness and elasticity, the implantation process may take longer, then late implantation can be diagnosed. Normally, the process of attaching the fetus takes about 40 hours. The thickness of the endometrium for blastocyst attachment should not be less than 7 mm.
From the first hours after the start of implantation, a specific hCG hormone begins to be produced in the woman's body, which sends a signal to the brain about the onset of pregnancy. 9-10 days after the intended conception, a blood test for pregnancy can be performed. Implantation in 30% of cases may be accompanied by bloody discharge, and, almost always, local pulling pains.
After implantation, the embryo continues to grow in the endometrium, which provides the supply of essential nutrients until the placenta is formed.
10 days after conception, pregnancy occurs directly - the fetus is already fixed and begins its formation. Immediately after the fetus is attached, the embryo consists of three layers of cells from which the skin, internal organs and the musculoskeletal system are formed. At 14-20 days after fertilization, the rudiments of the umbilical cord and placenta appear. These days, the primary circulatory system, the amniotic sac, is formed, the number of cells increases, the formation of all systems and organs of the child begins.
Embryo at 5 weeks
From 18 to 21 days after conception, the heart begins to beat in the embryo, which is easy to follow with the help of ultrasound, in parallel, on days 20-22, the baby forms the basis of the skeleton - the chord, spinal cord, brain and its departments. On days 24-26, the foundation of the central nervous system is laid.
At 3 weeks after conception, from 21 to 30 days, the baby's limbs, neural tube and visceral arches are formed. By the end of 1 month, the baby's muscle tissue, the rudiments of the eyeballs, and the spine are clearly visible. Further growth of the embryo involves the development of existing rudiments.
From the 5th week, the embryo enters the fetal stage.
At the 5th week from the moment of conception, the baby continues to develop all systems and organs, especially the brain. The primary sexual characteristics of the child begin to appear. Continues
From 6 weeks after conception, the child's ears, nose, eyes, eyelids, fingers and toes are formed. The heart is divided into chambers, the kidneys and ureters are formed.
1st trimester screening
At week 7, the umbilical cord and placenta continue to form, through which the fetus is provided with air and food. The brain by that time has a clear demarcation of the hemispheres, the formation of the fingers, palms of the child ends, the eyelids and eyes are already formed. The endocrine system kicks in.
At week 8, taste buds appear in the fetus, the gastrointestinal tract and oral cavity are formed. The outlines of the face are improved, the testicles are formed in the boys. The child's body begins to lengthen and the bones harden. By this time, the length of the embryo is 20 mm.
At the 9th week, the baby's adrenal glands begin to produce hormones, the circulatory system continues to form, and the prostate gland forms in boys. There are red blood cells in the blood at this stage, although there are still no white blood cells. The baby's joints and muscular system are already formed, so the fingers, knees and elbows can already compress. The formation of organs at this stage stops, all the forces of the pregnant woman and the baby are aimed at further improving the systems.
At the 10th week after conception, the first trimester ends. This period in obstetrics is equal to 12 weeks of pregnancy, since the countdown starts from the first day of the last menstruation. The first screening is recommended from the first day of the 10th week to the 6th day of the 13th week of pregnancy in order to identify possible malformations and determine the exact gestation period. The most accurate results are obtained by screening at 11-12 weeks.
As part of the first of two mandatory examinations, a pregnant woman needs to donate blood for hormone levels, Rh conflict, infections and undergo an ultrasound scan. An ultrasound examination evaluates the length of the fetus and the size of the head, the symmetry of the development of the cerebral hemispheres, the condition of the internal organs, the size of the bones, the size of the heart and tummy. During the examination, the doctor will be able to discern and prevent the development of pathologies.
Outcome
The development of a child from conception to birth is a rather complex and time-consuming process. The first trimester is the most important period of gestation, since at this time all the systems of the baby are laid and formed. At the end of the first trimester, a study is conducted that helps to track the compliance of the development of the embryo with the gestation period and prevent pathologies. For the expectant mother, screening is an opportunity to see the baby for the first time.
The first abdominal scan is one of the most touching moments of pregnancy, what do you think?
Many mothers ask themselves: when does the nervous system form in the fetus? Almost from the very beginning of cell laying. According to medical theories, all body systems develop unevenly in a baby. At first, those systems that are most important for the further activity of the baby in the mother's stomach begin to function. The laying of the nervous system in the fetus is manifested among the first most important processes in the development of the body.
Already at 8-9 weeks of pregnancy, gynecologists can see the first signs of the nervous system on the echogram. The second month is marked by the fact that the baby makes the first barely noticeable movements. Well, at 22-24 weeks, you can accurately see the baby who sucks the processes.
At what time is the fetal nervous system formed?
The nervous system of the fetus appears from a peculiar formation, which in medicine is called the neural tube. It subsequently must ensure the correct functioning of the whole organism. Before the tube appears, nerve tissue must grow, which consists of several types of cells. The first type is responsible for the main specific functions of the nerves, that is, these cells (neurons) are responsible for the actual regulation of the psyche. The second type provides proper nutrition to neurons and protects them from damage.
Nervous tissue under normal conditions of development of the child begins to develop already on the eighteenth day after the fertilization of the egg. At 3-4 weeks, the neural tube itself is already visible.
At what week is the fetal nervous system laid down? Already at the first! The nervous system is one of the first to develop so that the baby can continue to grow. If there are any problems with the formation of the nervous tissue, the fetus will soon die. Therefore, if you find out about pregnancy, try to immediately change your lifestyle.
What is a neural tube?
The formation of the nervous system in the fetus directly depends on the development of the tube. It is formed from the neural plate, which gradually closes into a tube, forming a small process - the rudiment of the future nervous system. If we consider the neural tube in section, we can see several layers: inner, marginal and intermediate. The intermediate and marginal layers provide the production of gray and white matter of the spinal cord, which is then located in the spine. In the inner layer, several processes take place at once: cell division and the synthesis of the future material responsible for the baby's genetics.
It takes the first weeks of pregnancy for the development of the baby's neural tube.
Development of the nervous system at 4-5 weeks of gestation
So, we found out at what time the nervous system of the fetus is formed. But what happens to her next?
The neural tube has some extensions, which are called cerebral vesicles. When the nervous system of the fetus is laid, three brain bubbles appear. One of them turns into the forebrain (it includes two hemispheres), the other into the visual center of the head, and the third into the rhomboid brain, which includes several more sections.
The marginal section of the neural tube also highlights a new organ, the neural crest, which is responsible for the development of several systems. At 4-5 weeks, only a black dot is visible on ultrasound. So far, this is all that has grown. However, for a child, this is already a lot, because at that moment the cells responsible for his brain were born in him. At this point, folic acid is essential for good neuronal development. Never treat your teeth in the first trimester! Any drugs, even local anesthesia, can reverse the normal course of cell division of the nervous system. Because of this, the baby may be born with abnormalities.
Development of the fetal nervous system at 6-12 weeks of gestation
When the nervous system is formed in the fetus, the mother should be at rest. The first weeks of pregnancy are therefore important because the health of the child depends on them. Already at 7-8 weeks, the baby is capable of reflexes. For example, it was observed that when his lips came into contact with the processes, he tilted his head back, thereby protecting himself from danger. This is how the defensive reflex develops. At 10 weeks, the baby is able to open his mouth if something irritates his lips. At the same time, a grasping reflex occurs when something bothers the baby's hand.
By the twelfth week, the baby can move her toes. From this, doctors concluded that those parts of the brain that are responsible for the lower part of the fetal body are the first to begin to function. Until the child reaches three months of uterine age, he will not be able to fully respond to irritations. His movements will be sharp and short. This happens because the excitation so far captures small areas of the nervous system. But the fetus grows and develops, and over time, its systems become more perfect.
Fetal development at 14-20 weeks of gestation
The norms of the development of the fetal nervous system can only be known with the help of ultrasound. If you have been told that the fetus meets all developmental standards, do not worry. But what is your child doing at this time? By the fourteenth week, the baby becomes quite active. If earlier he still could not move, then by the fifteenth week it is already possible to count about 15 new mastered movements of the baby.
When the nervous system is formed in the fetus, the mother feels the first tremors of the baby. They appear at 19-20 weeks. On ultrasound, it is already possible to distinguish between movements of the arms and legs, as well as hiccups, swallowing, yawns and other movements of the mouth. Between 15 and 20 weeks, the number of synapses, the places in the nervous system where signals are transmitted, increases. Due to this, the sphere of activity of the baby is expanding.
The condition of the fetus at 20-40 weeks of pregnancy
After the 20th week, when the nervous system is still being formed, the medulla begins to branch out in the fetus. This means that the exposed nerve cells will be covered with a layer of fat and will be able to fully function. The nerve impulses of the baby will be accelerated, and he will soon be able to replenish a number of his skills with new movements. The first to come into operation are the limbs of the fetus. The sense of smell is getting better a little later (about 24 weeks). In parallel with these changes, the brain develops, in which a framework for nerve cells is built.
It is noteworthy that the mass of the brain is up to 15% of the total mass of the fetus. After the basic processes in the brain have ended, it is time for another one - the destruction of certain types of cells. According to scientists, there is nothing terrible in this process. It's just that the body thus cleanses of unnecessary structures that have already done their job. So, when the nervous system is formed in the fetus, the body spends all its strength on its proper development.
Anomalies in the development of the nervous system in the fetus
When the nervous system is formed in the fetus, various kinds of anomalies and factors that appeared spontaneously can occur. For example, a fertilized cell began to multiply incorrectly and, as a result, it was damaged. Fortunately, the percentage of such defects is very low: up to 1.5 per 1000 born. It is known for sure that the cells of the unborn baby are destroyed both from environmental factors and from the genetic nature. The World Health Organization has established that the percentage of development of anomalies also depends on the nationalities and habitats of people. Here is a list of the main fetal developmental disorders:
- Absence of spinal cord and brain. This happens when the neural tube does not close. The skull and spine in this case are greatly exposed.
- Non-closure of the tube in the head compartment. This means that the child is brainless. That is, it has no hemispheres and subcortex. There is only a midbrain. Children born with such a violation live only the first months.
- Brain hernias. On the baby's head, protrusions of the skull bone or its tissues are found. Small hernias can be quickly removed.
- Hernias of the spinal cord. They are very common - 1 in 200. In place of some hernias, there may be strong hair growth. Children with this disease cannot walk, as well as relieve themselves.
The only way to deal with these diseases is surgery. In some cases, doctors cannot help. The child either lives with this deviation all his life, or dies shortly after birth.
Causes affecting the damage to the nervous system
Any factors that influence the destruction of the fetal nervous system present a complex picture. After all, it all depends on how long this factor acted on the child, whether it was very negative, etc.
- The first and main cause of all CNS lesions is the alcoholism of one of the parents. Toxins contained in alcohol are deposited in the body of the mother and father. When a woman has a child, all these harmful substances are transferred to new cells.
- Some drugs (for example, against convulsions) should not be taken during pregnancy at all. Therefore, if you have a disease that requires constant medication, talk to your gynecologist about it. He will definitely help you.
- Damage to the fetus cannot pass without a trace in the mother's body. A woman can get sick with infectious diseases (herpes, rubella, etc.).
- Also, the development of the fetal nervous system can be affected by mother's diseases (diabetes, hypertension) and genetic predisposition. Such troubles lead to chromosomal abnormalities that cannot be cured.
- Some defects, whether acquired or hereditary, may be mild. But they affect the overall development of the baby: autism, lack of attention, hyperactivity, various types of depression.
Try to lead a healthy lifestyle, because a child with a disability, born as such due to your negligence, will suffer all his life.
When the nervous system is formed in the fetus, the mother must take full care of proper food, proper rest and tranquility. Although gynecologists do not take into account the first two weeks of pregnancy, it is at this moment that your baby's first life systems are laid.
