Every woman dreams of becoming a mother. Already from the first weeks of pregnancy, when life is just emerging, we are waiting for a meeting with the baby. How nice it is to hug this warm lump, to hug and never let go. However, it will be a long nine months before the mother meets the baby.
It is generally accepted that a normal pregnancy lasts 9 months or 40 weeks. Permissible deviations are the birth of a child from 37 to 43 weeks. Babies born before 37 weeks are considered premature, and after 43 - post-term.
According to statistics, only 4% of women give birth exactly on time, and about 70% give birth with a deviation of 10 days before or after the appointed time.
Studies conducted by specialists from the National Institute for Health and the Environment in Durham, USA, have shown that such a difference in terms depends on a number of factors.
Older women have longer pregnancies, with each year of a woman's age adding one day to her pregnancy.
Women who themselves had more weight at birth, carried their child longer. Experts calculated that for every 100 grams of birth weight a mother added one day to her pregnancy.
Finally, if a woman's previous pregnancies lasted longer than the average, then the subsequent pregnancy was longer.
Human Reproduction magazine
From the moment of birth, each girl's body stores a huge, about 400 thousand, "reserve" of eggs, which are in an immature state in the ovaries. In the process of development, some eggs die, while others grow and acquire the ability to fertilize.
From the moment of puberty until the onset of menopause, the eggs mature in turn and exit the ovaries into the cavity of the fallopian tubes, where they are waiting for a meeting with the sperm. If the meeting took place, fertilization occurs and a new cell is formed, which, if successfully developed, will turn into a little man in nine months. 
Sperm rush to fertilize the egg
There are several concepts of pregnancy countdown:
They say that it is almost impossible, but from the first day of pregnancy I knew that life was born in me. Probably I had a very strong connection with my future son, or I really wanted me to get pregnant, but the very next day after being close to my husband, I was one hundred percent sure that I was pregnant. My forebodings did not fail me, and nine months later I gave birth to a wonderful son.
At 37 weeks of gestation, the baby is ready for independent living. All the baby's organs are already formed, the lungs are ready for breathing, and the body can exist outside the mother's body. Therefore, if a child is born at the 37th week of pregnancy, then such a pregnancy is considered full-term, and the birth is urgent, i.e. childbirth occurred on time or on time.
Pregnancy is counted by months or weeks. So, the average duration of pregnancy is 3 trimesters, or 9 months, or 40 weeks.
| Trimester | Month | A week | ||||
| 1 | 0 | 0 | 1 | 2 | 3 | 4 |
| 1 | 5 | 6 | 7 | 8 | ||
| 2 | 9 | 10 | 11 | 12 | ||
| 3 | 13 | |||||
| 2 | 3 | 14 | 15 | 16 | 17 | |
| 4 | 18 | 19 | 20 | 21 | ||
| 5 | 22 | 23 | 24 | 25 | ||
| 6 | 26 | 27 | ||||
| 3 | 6 | 28 | 29 | 30 | ||
| 7 | 31 | 32 | 33 | 34 | ||
| 8 | 35 | 36 | 37 | 38 | ||
| 9 | 39 | 40 | 41 | 42 | ||
A pregnant woman, keeping a pregnancy calendar, will not miss a single important moment and will receive an answer to many of her questions: when will the belly begin to grow, when will the baby move for the first time, etc. After all, within 40 weeks the baby grows and develops, and you need to watch out for any deviations in the development of the fetus. To do this, you need to do ultrasound on time, undergo screening and take tests.
To receive qualified medical assistance throughout pregnancy, the expectant mother must be registered with the antenatal clinic. So it will provide constant monitoring of the development of the child and the course of pregnancy. Visits to the doctor and the implementation of all his recommendations will help to identify the pathology or disease of the fetus in the early stages, start treatment on time or carry out prevention.
By registering before the 12th week of pregnancy, the expectant mother will also receive one-time assistance for the birth of a child from the state. This will help the family in the first time after the birth of the baby. To do this, a woman must contact the antenatal clinic at the place of registration or residence and submit the following documents:
So a woman will ensure constant monitoring of her health and the health of her child.
However, in European countries, pregnancy up to 12 weeks is not preserved. It is believed that the child must fight for his own future. And if a woman has a miscarriage, then the fetus has some kind of genetic disease, such as Down's syndrome, and the mother's body itself gets rid of the embryo. Therefore, doctors in Western countries do not interfere in the process of pregnancy up to 12 weeks.
Doctors of Russia are more loyal. They are fighting for every future man of the country. If the fetus has no abnormalities, then the woman is placed in storage and treatment is prescribed. In early pregnancy, abnormalities may be due to placental abruption, uterine tone, or a lack of the hormone progesterone. A pregnant woman is given appropriate treatment.
Generally indicates the end of the first trimester of pregnancy. From this period, the manifestation of toxicosis decreases, and the embryo inside the woman is now called the fetus.
Every woman dreams of becoming a mother, but not everyone succeeds. Some women, for various reasons, cannot become pregnant naturally, then doctors resort to IVF fertilization. 
When a couple fails to get pregnant on their own, IVF fertilization comes to the rescue
The older a woman becomes, the lower the effectiveness of artificial insemination. According to IVF statistics, the long-awaited pregnancy ended in women depending on age:
It is possible to say that IVF was successful only two weeks after the last IVF procedure. To do this, a woman takes a blood test for hCG, and the doctor, based on the results of the tests, determines whether pregnancy has occurred or not.
To control the course of pregnancy and the development of the fetus, a woman is screened - a comprehensive examination. They include ultrasound and biochemical analysis of venous blood. However, in our country this is not a mandatory procedure. Screening may be prescribed if any pathology or abnormalities are observed.
There are a number of cases where screening is indispensable. It is required:
For the entire duration of pregnancy, screening is carried out three times: in the first, second and third trimester:
Having become pregnant, a woman should be prepared that within 9 months she will have to pass a lot of various tests. Some she will take all the time, others will pass only once in her entire pregnancy.
At the first visit to the gynecologist and registration at the antenatal clinic, usually this happens before the 12th week of pregnancy, you will need to pass the following tests:
All tests were passed, the woman was registered with the antenatal clinic, and now, at each visit to the gynecologist, the woman must take a general blood and urine test, and her weight and blood pressure are also measured during the visit.
| Analyzes | 1 trimester | 2 trimester | 3rd trimester |
| Clinical blood test | At every visit | At every visit | At every visit |
| Clinical analysis of urine | At every visit | At every visit | At every visit |
| Blood sugar test | 8–10 weeks | 30 weeks | |
| smear on flora | 8–10 weeks | 20 weeks | 38 weeks |
| Blood test for HIV, syphilis, hepatitis B and C | 8–10 weeks | 30 and 38 weeks | |
| Blood clotting test | When registering | 30 weeks | |
| ultrasound | 10–14 weeks | 20–24 weeks | 32–36 weeks |
| Prenatal diagnosis | Double test (blood test for hCG and PAPP) 8–13 weeks | Triple test (blood test for hCG, AFP, free estriol) 16–18 weeks | |
| Examination of the cervix for ICI | 16–18 weeks | ||
| Movement test | from 28 weeks | ||
| CTG (cardiotocogram) | weekly from 32 weeks | ||
| Doppler study | 30–32 weeks |
A woman, having become registered with the antenatal clinic, will also receive information from the doctor about the things needed in the maternity hospital and the date by which they need to be collected.
I have three kids. I started collecting bags gradually, starting at 20 weeks. This is not so expensive, and there is still time to think about what is needed. By 35 weeks I had my bags ready.
In general, every woman is an individual, therefore, the approach to cooking things is different for everyone. Someone begins to prepare only after learning about pregnancy, while someone, on the contrary, pulls to the last and at 38 weeks runs around in search of the right things.
Each time I collect for a period of 10-14 weeks ... Don't ask why! Oddity! And then the most entertaining - the tummy grows and the bag grows !!! Just before the maternity hospital, the husband, laughing, clarifies: did you decide to pick up the children and quietly leave me?! ….. Well, or: don't you take the piano? Strange, but what about the development of a sense of beauty in a child?! ……. Like this
Shunechka
39 weeks - contractions - and I’m flying around the apartment collecting bags, I haven’t had time to wash the children’s things yet ... as a result, I’m already in the delivery room, and my sister irons the children’s things at home, they barely managed to transfer them to the delivery room. So it’s better as the girl wrote above ... with a piano, but calmly!
Babaiko
https://sovet.kidstaff.com.ua/question-162319
During pregnancy, a woman may face such dangerous moments as a miscarriage or premature birth:
The timing of childbirth in women varies for a number of reasons. So, in primiparous women, childbirth occurs later than in multiparous women. This is due to the fact that the birth canal of the primogeniture is not yet prepared, the cervix opens slowly, and childbirth occurs later.
There is also an opinion that girls are more active and are born before boys.
I completely disagree with this. I gave birth to my two boys at 38 weeks, while the princess was in no hurry to get to know us. I gave birth to my daughter at 41 weeks.
In a study of 11,000 births, birth statistics were compiled by week:
Each week of pregnancy brings something new in the sensations of a woman and the development of the fetus. 
How does the development of the fetus every week
| A week | Changes that occur every week in the body of a pregnant woman | |
| 1 | The egg matures and prepares it for release from the ovary. | |
| 2 | The egg is actively developing. By the end of the second week, ovulation occurs. | |
| 3 | Fertilization of the egg. By the end of the third week, the embryo implants and the placenta is formed. | |
| 4 | The first signs of pregnancy appear: swelling of the mammary glands, nausea, pulling pains in the lower abdomen | The embryo is actively developing. Internal organs and the nervous system are laid. The umbilical cord is formed. |
| 5 | Tests 100% confirm pregnancy. A woman has signs of toxicosis, fatigue, drowsiness. | The placenta and the membrane of the fetal egg develop. The reproductive, nervous and circulatory systems are formed. As well as the upper respiratory tract, liver and pancreas. |
| 6 | It's time for a woman to see a doctor and register with a antenatal clinic. | The neural tube tightens and the brain begins to form, facial features develop, arms and legs form. |
| 7 | The woman continues to worry about toxicosis. Due to hormonal changes, the condition of the skin and hair worsens. The uterus increases in size and this leads to frequent urination. | There is an active development of the internal organs of the child: the heart becomes two-chamber, the lungs develop, the small intestine is laid, the esophagus and trachea develop. |
| 8 | In a woman, signs of toxicosis increase, as well as weakness and fatigue. | In this period, almost all important organs are formed. Further, they only improve, grow and develop. |
| 9 | Toxicosis torments a pregnant woman even more, which can lead to weight loss. There is swelling of the mammary glands. | The embryonic stage of the development of the baby ends. The child has a pituitary gland and a cerebellum. |
| 10 | If a woman's toxicosis is accompanied by vomiting, then she loses weight. If there is no toxicosis, the woman gains 1.5–2 kg in weight. | Part of the child's organs are already working - these are the intestines, kidneys, liver and pancreas. Also, the baby can move and swallow. |
| 11 | Hormonal balance returns to normal, metabolic processes increase, and the volume of circulating blood increases. | The baby develops a grasping reflex, the formation of the sternum, diaphragm and genitals is completed. The baby's intestines begin to work, and his liver is already producing blood. |
| 12 | Pigmentation may occur, a dark line from the navel to the pubis, which will disappear after childbirth. | The child is actively developing. He can roll over, open his mouth and wiggle his fingers. The genitals are formed, the liver begins to produce bile. |
| 13 | The uterus increases in size and rises into the abdominal cavity. | The skeletal system is actively formed, and the respiratory system is already well formed. The thyroid gland is well developed, and the pancreas produces the first insulin. |
| 14 | The body of a woman is preparing for the role of a mother, and the desire to prepare a corner for the baby wakes up. | The face already looks like a newborn. Your baby's taste buds are developing. |
| 15 | Toxicosis recedes, urination normalizes, however, leg cramps may begin, which may indicate a lack of calcium, magnesium or potassium. | The cerebral cortex, the central nervous system are formed, the endocrine glands of the fetus develop, the respiratory system develops, taste buds are formed. |
| 16 | Due to changes in the hormonal background, namely due to an increase in the hormone estrogen, which provokes swelling of the nasal mucosa, 30% of women may experience rhinitis during pregnancy. | The liver, kidneys and bladder perform their functions. The composition of the blood includes all the necessary elements: erythrocytes, lymphocytes and monocytes. |
| 17 | A woman gains from 3 to 6 kg. In this regard, the load on the legs increases, which begin to swell and hurt. | The organ of hearing is formed, the formation of the conducting system of the heart is completed, the swallowing reflex develops. The skin is covered with a special fluff. |
| 18 | Weight gain provokes the appearance of pain in the back and lower back. There may be a discharge from the vagina. | The baby's immune system and hearing organs are formed, the heart is actively working. |
| 19 | Due to the fact that for the full development of the baby, a lot of calcium is needed, and if it is lacking, it is taken from the woman's teeth, the expectant mother should pay attention to their condition. It is advisable to visit a dentist. | The brain develops, connections between the nervous system and muscles are established. The respiratory system of the baby is created, which includes the lungs, bronchi and bronchioles. |
| 20 | Increased vaginal discharge. Possible development of varicose veins | The child develops subcutaneous adipose tissue. |
| 21 | An enlarged uterus can cause heartburn, and a growing belly can cause back pain and stretch marks. | The endocrine glands perform their functions, the nervous system develops, the digestive tract works. The spleen begins to work. |
| 22 | A woman's gait changes, edema and varicose veins appear. Baths from herbal infusions or massage will help to cope with them. | All the internal organs of the baby work smoothly, and the liver begins to produce a variety of enzymes. |
| 23 | A woman should start preparing for childbirth and pay enough attention to her physical condition. | The pancreas begins to produce hormones, including the main one - insulin. |
| 24 | There is a risk of developing anemia, in connection with which a woman needs to pay attention to her diet. It should be complete and contain a sufficient amount of vitamins and minerals. | All sense organs are formed. The baby begins to prepare for the birth. |
| 25 | The expectant mother gains weight, the manifestation of pigmentation intensifies: the peripapillary zone darkens and the strip from the navel to the pubis appears more clearly. | The development of the bone marrow is completed, but the bone tissue is formed further. The fetal heart rate is 140-150 beats per minute. |
| 26 | It will not be superfluous to purchase a prenatal bandage. It will help take the pressure off your spine. | The rudiments of teeth are formed, the bone apparatus is strengthened, muscles increase. |
| 27 | Often a woman is haunted by constipation. Many people experience high blood pressure and may also feel hot or sweat excessively. | The baby is proportionally developed, his appearance is like that of a newborn child |
| 28 | Due to weight gain, lower back pain appears that covers the thigh, sometimes even reaching the ankle. A lack of calcium in the body of a future mother can trigger seizures. | The baby continues to grow and develop. The respiratory system is fully formed. |
| 29 | An increase in the weight of the expectant mother and squeezing the lower pelvic vein provoke a violation of the outflow of blood from the lower body of a woman. This in turn leads to varicose veins, hemorrhoids and constipation. An enlarged uterus can cause shortness of breath and heartburn. | Blood contains all the necessary substances, it can carry oxygen, protect against infections and bleeding. |
| 30 | The high level of progesterone accumulated in the body of a pregnant woman provokes hypersensitivity and engorgement of the mammary glands. | The respiratory system is formed, now the baby is training the lungs so that at birth he can breathe. |
| 31 | Women should pay attention to the regularity of the stool, in many it is disturbed and accompanied by flatulence. A significantly enlarged uterus does not allow a woman to rest on her back. In this position, her head is spinning and she becomes ill. | The brain is actively developing. The weight of internal organs increases. |
| 32 | The baby has grown enough and now tossing and turning in the tummy gives mom inconvenience. Many pregnant women toss and turn all night long, choosing a comfortable sleeping position. | The baby's immune system is being formed. Now, when receiving immunoglobulins from the mother, the baby's organs begin to produce antibodies, creating protection for themselves for the first months after birth. |
| 33 | Now all the thoughts of a woman are occupied by the upcoming birth. She becomes anxious and restless. The lack of calcium, as well as the accumulated excess fluid in the body, provoke the appearance of seizures. | The baby has already grown enough and is quite viable. If suddenly a woman begins premature birth, the newborn will be able to exist independently. |
| 34 | Many women experience uterine contractions, they are also called false contractions. The uterus of the expectant mother has increased several dozen times. | The baby is already ready to receive the first food, but for now, his intestines receive only amniotic fluid, which is processed into the original feces - meconium. At birth, meconium will pass out of the body of the newborn. |
| 35 | A huge burden falls on the body of a woman during pregnancy. And it is not only physical, but also psychological. Women are scattered, forgetful, it is difficult for them to concentrate. | The development of the adrenal glands, which contain hormones responsible for water-salt and mineral metabolism, is observed. |
| 36 | There is a gradual aging of the placenta. Intensive aging of the placenta can cause fetal hypoxia (oxygen starvation), which in turn will lead to impaired development and growth. | The child has already grown enough and it is already cramped in the womb. His movements are constrained, and pushes and turns are painful for mom. |
| 37 | Mucus plug begins to stand out. During pregnancy, she played a protective role. The cervix begins to prepare for dilation. | The baby is ready to meet his mother. The nervous system continues to develop. |
| 38 | The fetus begins to move down, and puts pressure on the pelvic bones. This causes pain in the woman. The woman's breasts fill up, and the nipples become very sensitive. | The muscles of the child in the required tone. The kid continues to wait for the meeting. |
| 39 | Pain in the back and lower back, swelling and constipation, varicose veins and heartburn continue to bother a pregnant woman. | In anticipation of the meeting, the baby moves into the pelvic cavity of the mother. |
| 40 | The ideal option is childbirth. Even if they did not occur this week, the uterus has already descended, thereby alleviating the condition of the pregnant woman. Now the expectant mother breathes easier, and an actively working stomach eliminates the manifestation of heartburn. The descended fetus presses on the genitals, and the woman experiences heaviness and pressure in the perineum. | A significantly aged placenta is no longer able to perform the functions assigned to it. This is very dangerous for the unborn baby, since the lack of oxygen leads to problems with the functioning of the brain and internal organs. |
| 41 | Ideally, a woman should have given birth by now. The body is constantly preparing for this. If a woman has not done this before, then urgently you need to start preparing the breast for breastfeeding. | The baby is ready to be born, he does not have enough space in his tummy, he cannot even move. |
And now the long-awaited meeting has come.
Congratulations, you are the most caring mom if you want to learn about the development of the embryo by day from conception. This is useful, as you will be able to keep abreast of what is going on inside you. And the more we know, the less we panic about the little things. Ready?
Pregnancy is generally divided into two main stages:
The entire term of a standard pregnancy lasts 9 months, while the term is considered not according to the calendar month, but according to the obstetric one, which takes 28 days.
1 – 4 days
As soon as the sperm enters the cell, the process of division takes place. One cell turns into 2, and they already into 4. All the first 4 days the cells are only engaged in division. Until the end of this short period, 58 cells will appear, which are called blastomeres. 5 cells are needed for the direct development of the fetus and the connecting umbilical cord. The rest is for food. At this stage, the growth of the embryo does not exceed 0.14 mm.
Day 5
The blastocyst is a vesicle that appears on the fifth day. Fluid accumulates in the bubble. Over time, the blastocyst will grow.
6 – 7 days
The embryo should already be attached to the uterus. This is the so-called implantation. At this point, a woman may be disturbed (be sure to read), but this is completely normal and there is nothing to worry about. Although if they are not, then everything is fine too. Allocations can simply warn that pregnancy has begun and now the body will adapt to the new period.
Day 8
The fetus is already inside the uterus and feeds on substances from the blood of the mother's body.
The second and immediately the third week, which includes the 9th to 21 days, is the period of active formation of the placenta, umbilical cord, and neural tube. As for the latter, it is with it that the nervous system begins.
Each stage is important in its own way, but it is in the second and third weeks that the foundation of the future organism is laid. That's why it's so important. It helps in the formation of all major organs.
And most importantly at this stage - the heart begins to beat.
By day it is 22 - 25 days. Now the rudiments of the brain, pancreas, lungs, and liver are being formed. There is a basis for the future to form arms and legs. The neural tube at this stage has already formed and the nervous system is formed from it. Folic acid is still essential.
29 - 35 days - this is the second month. At this time, the most important organs appear. In the digestive system, the liver and pancreas are already fully formed, in the respiratory system - the trachea, larynx and lungs. There is already a hematopoietic system.
Eyes appeared, which are still on the embryo located on the sides. Later they will take their usual position. The inner ear is formed.
In the nervous system, attention is focused on the brain, now its departments are being formed.
Sex cells are just appearing in the reproductive system, but nothing can be said about a specific field yet.
The arms and legs are already forming with might and main, even nail plates appear. A barely noticeable umbilical cord is gaining momentum.
At this stage, the weight of the embryo barely reaches 0.4 g.
From the 36th to the 42nd day in the sixth week, the placenta appears. It is not yet connected by blood circulation with the embryo.
The encephalogram is already able to capture the first signals from the brain, because it is already developing with might and main.
Muscles appear on the face, the eyes are already more visible, but they are not yet covered by eyelids. Fingers appear on the hands.
The heart, which is already beating with might and main, forms chambers. The kidneys and ureters are formed.
As for the digestive system, after the work on the pancreas and liver is completed, the cells line up the intestines and stomach.
In the period from 43rd to 49th days, the umbilical cord has already formed. Together with the placenta, they provide the fetus with air and food. The system of hormones is launched, which is reflected in breast enlargement in the mother.
The body is still poorly developed, and most of it is occupied by the head. There is a tail in the pelvis, which will then disappear. The fingers are already formed, but not yet separated. The first spontaneous hand movements appear.
At the seventh week, the mouth already opens and there are eyelids for the peephole. Nose and ears are formed.
These are days 50 to 56. The body is growing, lips, eyes and nose are well drawn. If it is a boy, then the testicles gradually develop. The fingers are already separated. The bones are getting stronger.
56th day - the growth of the fetus barely reaches 20 mm. In appearance, it is no larger than a chicken egg and consists of 97% of the liquid.
At this stage, the embryo is already considered a fetus. All the main organs for vital activity have been formed and now the stage of their improvement is coming.
57 - 63 days
From the third month of pregnancy, reflex movements appear. The cartilages of the larynx and ears are noticeably formed. The adrenal glands even produce hormones. The brain continues its active growth.
The heart is capable of producing 150 beats per minute, and it is already pumping blood through the vessels.
At this stage, there are only erythrocytes in the blood, and there are no leukocytes yet, therefore, the mother's body protects the fetus from infections. This is the so-called passive immunity.
The fingers can already be compressed, because the joints are formed. The fetus makes its first movements.
64 - 70 days
It's time for the ponytail to disappear. Buttocks are actively developing.
The respiratory system is almost formed and is even ready for independent work.
Movements are no longer chaotic, but react to external stimuli. Mom will not feel this yet, because the size of the fetus reaches a maximum of 40 mm, but if you press on the area of \u200b\u200bthe uterus, the fetus will bend the arm or leg. Can turn his head.
71 - 77 days
Now the eyes are not just formed, but the iris has already been drawn. And this means that the baby already has a certain eye color.
At this stage, the expectant mother may experience slight discomfort, such as weakness, pressure, nausea. This is due to the development of hormones.
78 - 84 days
Remember, we talked about the fact that there are no leukocytes in the cells of the fetus yet? Now they appear and are able to protect the body of the unborn baby. Parts of the body are already formed and are clearly visible.
85 - 91 days
Now all the internal organs in the body of the fetus are fully formed. The child begins an overactive growth of the skeleton, and if there is not enough calcium in the mother's body, it's time to replenish it.
92 - 98 days
Eyebrows and cilia appear on the face of the unborn child. The baby can make facial movements for the first time.
You can already hear the beating of the heart if you use an obstetric stethoscope.
99 - 105 days
Now it's time for gender formation. And in the meantime, the pancreas is already coping with the production of insulin.
106 - 112 days
Fingers and nails are already formed on them. If you look at the baby on the ultrasound machine, you can see how the child sucks his thumb. By the way, at this stage of formation, the baby can already distinguish between smells and tastes.
Get ready for the first moves.
113 - 119 days
The teeth are just starting to develop. At birth, they will not appear yet, but their foundation is laid just in the womb. The child already has hearing, which is why the baby may move slightly at loud sounds.
120 - 126 days
At this stage of development, the baby reaches a maximum of 190 mm. You may feel the baby move.
127 - 133 days
Now, not only do you feel the fetus moving, but others, in contact with the stomach, will feel it. By the way, if you are giving birth for the first time, then do not worry that you did not feel movements before, they often appear in primiparous on the 127th day.
The blood of the fetus is filled with a new composition - erythrocytes, leukocytes, monocytes, lymphocytes.
134 - 140 days
It is time for the formation of the fatty layer. As for facial expressions, it continues to develop. Now the baby can already smile, blink his eyes or frown.
141 - 168 days
The fetus is already large enough to occupy the entire uterus. The baby can react to light and sounds, and the emotions that the mother feels are also felt by the child. Be mindful of how you feel, try to listen to classical music and meditate.
The baby is able to swallow, so now he swallows amniotic fluid and a lubricant that protects the skin. This is normal and necessary for the bowels to work well. Lubricant and amniotic fluid turn into meconium during processing.
169 - 196 days
Alveoli form in the lungs, they look like deflated balloons. When the baby inhales air for the first time, the alveoli will straighten out. Now they are still able to produce the surfactant that is required for their normal functioning.
If you are carrying a boy, then the testicles descend into the scrotum. If a girl, then external genitalia are formed. The brain becomes more and more active.
197 - 224 days
This month, the baby should take the position necessary for birth - head down. There are times when the baby does not roll over properly. Then . This question must be clarified with a doctor.
Almost all systems and organs in the baby's body hone their work so that at birth they already function without the help of the mother's body.
Since the child's eyes are already reactive to light, the pupils may constrict and dilate. Please note that tremors can only intensify.
Nothing phenomenal compared to the first days is happening now, but the mass is quickly gaining. The increase can reach up to 35 g per day.
Mom is also seeing changes. A hormone is produced, due to which milk will appear.
Surely you have already heard that children can be born at the 8th month. As you can see, the child's body is quite capable of functioning.
225 - 252 days
Now time is running out. Here comes the birth. And the baby is preparing for this event. His head, or rather, the cranial bones are mobile enough to pass through the birth canal. The baby doesn't turn around anymore.
253 - 280 days
The weight of the baby reaches 3.5 kg with a height of 0.5 m. Intrauterine development is fully completed and now the child is ready to be born.
This is how the embryo develops day by day from conception. Bookmark this page to always remind yourself of the path your baby has taken since conception. Take care of yourself.
Read this article:
The birth of a new life is the most beautiful mystery of nature. What could be more mysterious than the development of a child in the womb? The formation of a little man from a fertilized egg goes through a rather complicated path. Expectant mothers will be very interested to know how the intrauterine development of the child takes place by week.
Pregnancy lasts 40 weeks or 10 obstetric months. The term "obstetric month" means 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 entered the egg and formed a single cell with two nuclei. These nuclei, moving towards each other, form a zygote. A zygote is a single-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 the following 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 increases intensively.
By the seventh day, the embryo already consists of hundreds of cells. On the eighth day, the embryo is attached 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. A small embryo already on the 3rd day of its life begins to produce a hormone - gonadoprin. All pregnancy tests are sensitive to this hormone.
At the end of 4 weeks, a woman discovers the absence of menstruation. The first symptoms of pregnancy will appear: nausea, dizziness, drowsiness.
During this period, the embryo is already commonly 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:
If we divide the entire pregnancy into 3 equal periods, we get the following time periods: the first, second and third trimesters. Each trimester lasts 3 months.
If a woman is not yet aware of her “interesting position” and continues to lead an inappropriate lifestyle, then the embryo will most likely die at the stage of blastogenesis. If the mother's destructive lifestyle does not change during the first 12 weeks, there is a high probability of miscarriage.
The development of the embryo is a key moment of pregnancy, since during this period all vital organs are laid, which will affect the health of the baby in the future.
In no case should mom 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 into the gastrointestinal tract in the future. 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 on, the “heart” begins to beat in the embryo. 
A groove forms 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 contributes to the full formation of the nervous system of the unborn child.
At 6 weeks, the embryo takes on a C-shape. During this period, the laying of the primary intestine, cartilage of the skeleton, liver, kidneys, and thyroid gland occurs. The small embryo reaches 4 mm.
At the 7th week of pregnancy, toxicosis appears in women. This period is characterized by intensive development of the brain. The mouth and eye sockets begin to form. The respiratory system is actively developing, the heart begins to divide into chambers and arteries, the spleen and gallbladder are formed.
At week 8, with the help of ultrasound, the first movements of the embryo can be recorded.
At week 9, the fingers on the upper and lower extremities are determined, 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 fetus already has taste sensations.
At week 10, the membranes between the fingers disappear, the tail disappears. The sex of the child is still difficult to determine at this age, but the production of testosterone is already beginning in boys.
By week 11, the embryo weighs 5 g with a size of 3 cm. This is the final stage of embryonic development, subsequently the embryo will be called a fetus.
At 12 weeks, almost all organs have formed in the fetus 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, ultrasound is performed, which determines the quality of the child's development, genetic abnormalities.
If intrauterine abnormalities are found in the fetus, then the woman is recommended to undergo additional studies. But the final conclusions about chromosomal disorders 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, it can be the other way around: the percentage of talented children born is higher just for older parents.
At week 13, the external genitalia differentiate. However, they can be distinguished already at 14-15 weeks with the help of ultrasound. At this stage, the formation of the intestine occurs. The baby is fed 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 proportion 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 mother's timbre of voice, music.
That is why it is important for expectant mothers to listen to beautiful classical music, thus instilling good taste in the baby.
At week 15, the blood vessels of the fetus become visible, which are enlightened through thin skin. The skeleton and bone marrow continue to form.
At 16 weeks, a planned ultrasound is performed, on which you can notice the movement of the baby's eye. The legs have become proportional to the length of the body and small nails begin to grow.
At 17-18 weeks, the small body is covered with a primary fluff - lanugo. This is such an original lubricant that protects the skin from the aquatic environment. During this period, fingerprints are laid, which are genetically predetermined.
The weight of the crumbs is 200 g with a height of 14 cm.
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.
Starting from the 20th week, the rudiments of teeth form in the baby. The baby's hair grows more actively on the head, but their pigment is formed a little later.
From 22 weeks, mothers begin to feel how the baby is pushing. His weight at this time 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. There is an active development of the brain.
The muscular system and internal organs continue to improve actively. The respiratory system is getting more and more developed. In the intestines of the baby, the first feces accumulate - meconium.
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 food addictions are formed in the child. It is important for mothers to understand this and try to avoid spicy and bitter foods, as the little baby prefers sweets more.
The beginning of the third and final trimester - 27 weeks. 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 light tremors to the mother.
A child born at this time can survive with certain care. He is 37 cm tall and weighs 1150 g.
For women who are preparing to become mothers of a healthy baby, of course, it will be superfluous to talk about the right lifestyle. Alcohol, cigarettes, lack of regimen, sleep and rest are very detrimental to the health of the unborn child.
At 30-32 weeks, the fat subcutaneous layer of the baby becomes thicker. Some babies are already turning head down at this stage.
Convolutions appear on the surface of the small brain. Pupils can already detect bright light. When conducting an ultrasound at this time, you can notice how the baby closes its eyes from bright light. For this reason, it is important to avoid ultraviolet rays and give up a beach holiday.
From 33 weeks, the little man is already getting cramped in his mother's tummy. At this time, the fetus turns head down, preparing for childbirth.
If a premature birth occurs at this stage, then the baby has every chance of surviving. However, he will be considered premature and will need special care in the hospital.
The skin of the baby 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. Vellus hair on the body thins out, and on the head it grows intensively. The child every day is gaining 30 grams of fat.
By this time, the stomach drops, and it becomes easier for the mother to breathe. This usually happens two weeks before delivery.
By this time, the baby is ready to see the light. He is very cramped inside his mother: his knees are tightly pressed to his chin.
At week 39, the body becomes clean: the fluff remains only on the shoulders. The intestinal system of the crumbs is filled with meconium and amniotic fluid.
At 40 weeks, prenatal development ends, and a new person is born! A newborn photo becomes almost the most important photo in the house. After all, what could be more exciting and beautiful than the birth of a small miracle!
The stages of pregnancy take place according to a well-defined calendar. As a rule, specialists are guided by the obstetric calendar. When describing pregnancy by week, the development of the fetus and the sensations of both the woman and the child themselves are of the utmost importance. Often, pregnancy is tracked by months, but this is usually done by women themselves, for whom a period of 5 months looks better and more pleasant than 20 weeks. After all, it visually seems that the wait is less.
Doctors also give the stages of pregnancy by trimesters and weeks with a description of everything that should happen during this period.
The first trimester of pregnancy is a stage from 1 week to 13-14 weeks. It is extremely important, because it is at this time that the main laying of all systems and organs of the fetus takes place. It is during this period that a woman should be protected from various infections and bacteria. After all, each of them can cause deformities in the fetus. Often, infections transferred in the early stages cause intrauterine death of the fetus.
The 1st week obstetric is the week in which the woman is still menstruating. At the same time, in fact, she is not pregnant, but she will soon become so, because. she starts a new cycle of ovulation. If a lady is planning a pregnancy, she should take care of her child in advance - she should start drinking folic acid and magnesium as a means that will strengthen the body and enable her to prevent various pathologies in the fetus.
2nd week the beginning of the ovulation cycle, the egg begins to mature and go into the tube. It should be understood that the period of her life is only one day. In this case, spermatozoa can live in the body of a lady from 3 to 5 days. And if sexual intercourse occurred exactly before the release of the egg, the woman has a great chance of giving birth to a boy. If they have been in the body of a lady for several days6, then a girl is more likely to be born. This is due to the fact that spermatozoa with the X chromosome are much stronger and more enduring.
3rd week - the time of the formation of the zygote and its transition through the tubes into the uterine cavity. The development of pregnancy begins. A real hormonal storm is raging in the lady's body. But it is necessary, because. it is the increased production of hormones that allows you to save the pregnancy by relaxing the muscles of the body. Embryo implantation occurs, there may be slight bleeding when the fetus is attached to the uterine lining. With him, except for active division, nothing happens yet. In essence, the child is still a small set of cells, but at the same time he feels everything.
4th week - during pregnancy, the development of the fetus begins at this very moment, it gradually begins to appear in the usual form of a baby. Gradually, his head is formed, the heart begins to gather (it can be heard already at 6-7 weeks of pregnancy), the body takes the form of a seahorse.
At the 5th week, the baby is still quite tiny - no more than a grain of rice, it is a 3 mm organism. The yolk sac, which is formed during ovulation, begins to produce the first sex cells of the baby, which, when transferred to the baby's genitals, will become either sperm or eggs. The child develops a chord, which later will begin to perform the functions of the spine. In the same period, the formation of the trachea, larynx, thyroid gland, pancreas and liver is noted. The child's nervous system is developing very actively. The neural tube closes, which later becomes the spinal cord.
By 6 weeks, the size of the baby is 4-5 mm. It is believed that this period is a key moment in the development of the child's nervous system. He has a complete closure of the neural tube, which is tightened by the tissue. And by the end of the week she will have all the basic features of the human nervous system. Also in the fetus, the appearance of the rudiment of the brain is noted, and even the first nerve connections begin to appear. The brain begins to appear cavities and convolutions. The heart begins to work in conjunction with the activity of the brain. At the same time, despite the fact that the heart is immature, the process of blood circulation begins to work - in this situation with the help of the liver. The child's arms and legs begin to appear, and soon it will even be possible to see the rudiments of fingers. At the same time, eye sockets and a mouth begin to form on the face. Although the baby is still small, he is already beginning to feel, and his inner ear is forming. The immune system of the crumbs also begins to form. The development of the baby's internal organs - lungs, liver, stomach, pancreas - continues. The placenta begins to receive its active development.
The 7th week is characterized by the further development of the child at a rather active pace. The heart is already divided into 2 atria and has 4 chambers. Large blood vessels begin to form. The intestines and pancreas with the liver grow and expand. The formation of the lungs, kidneys, bronchi and endocrine glands continues. The child's eyes receive cilia, pigment is laid in the retina and iris in the eyes, and the face continues to form. The baby's arms develop faster than the legs, even elbow bends are noted in the wrist area. The baby already has palms. The baby even begins to move, but since he is still very small, the mother cannot feel these movements in any way.
The 8th week is the period of further growth and development of the fetus. He continues to move quite actively through the uterine cavity, but the mother still does not feel him yet, because. its dimensions are too small. Now he is 14-20 mm in size, and weighs about 3 g. He is already more and more like an ordinary baby - his ears are looming, his nose and upper lip are showing. During this period, the laying of all the main systems and organs of the fetus was completed, a period of their active development and functioning is noted. The heart is strengthened, the nervous and respiratory systems are actively developing. In the stomach, the production of gastric juice begins, the kidneys are already working on the production of urine. The bones and muscles of the crumbs develop very rapidly. Taste buds have already begun to form on the tongue.
9 weeks of pregnancy are characterized by the beginning of the third month of pregnancy, when the expectant mother is already aware of her situation and is suffering from toxicosis with might and main. The child during this period is 22-30 mm in height, and weighs only about 4 g. The embryo is actively straightening out, and atrophy of its tail will soon begin. At the 9th week, the fetus begins to actively interact with the mother, sending her signals with its brain, for example, this can manifest itself in a change in women's taste preferences. The genital organs are actively formed, but at the same time it is still impossible to find out the sex of the baby. The formation of nerves is noted - both intervertebral, and spinal and cranial. The child's forearms and shoulders are already visible, the limbs begin to bend. The body of the child is gradually overgrown with muscles. The rudiments of nails appear in the hands. At the same time, the body continues to be uneven - the head is larger than the body. The kid knows how to wrinkle his lips and is even starting to swallow. Now the child begins to excrete the products of his life into the mother's body through the umbilical cord. And this means that a woman should take care of her kidneys, which are experiencing a double load.
The following parameters are characteristic for the 10th week of the baby's development: height 4 mm, weight 5 g. Now the baby already resembles a real person. While it remains transparent, and the hair is only laid in the body. The heart is already beating very actively - the pulse often has 150 beats per minute. The brain receives special activity in its development - 250,000 neurons are created in it in 1 minute. The nervous system is divided into central and peripheral. The baby is laying milk teeth. Therefore, mothers should replenish their diet with foods rich in calcium. Otherwise, the fetus will take everything from her body, destroying it significantly, leading to cramps, brittle nails, and deterioration of the teeth. The liver continues to develop, the ducts in it are already fully formed.
The 11th pregnancy is characterized by the growth of the child up to 5 cm, its weight is 8 g. It is from this time that it begins to grow in a particularly active and fast way. Due to this, in just a couple of weeks, its length will increase by 2 times. The heart of the crumbs during this period works like an adult - now it supplies the organs with blood. The placenta becomes stronger every day, more blood vessels appear in it - this helps it meet all the growing needs of the child. The embryo is now officially called a fetus. During this period, the intestine, despite the fact that it has not yet fully formed, begins to give out movements similar to peristalsis.
The fetus at 12 weeks is almost completely formed. Its organs and systems work extremely actively. The fingers on the hands are separated, a fingerprint begins to form, which is unique. The baby is already quite active, can grimace, take a finger in his mouth. He continues to move more and more actively in the mother's stomach.
13 weeks of pregnancy pass, and the child becomes more and more like a normal baby. His muscles and bones continue to actively form, the pancreas produces the first insulin, and the villi necessary for the normal maintenance of the digestive process are formed in the intestines. The heart pumps up to 23 liters of blood per day. In terms of height, the child has reached 8 cm, and now he weighs 15-25 g. Now the baby is already streamlining his daily routine more - he sleeps less, begins to learn to control his body, moving more carefully. Now he can already feel the taste of the food that his mother eats, and against this background he forms his own taste sensations. Right now, a woman is recommended to start communicating with her baby - this will allow her to establish contact with him and give him an incentive to develop more correctly.
The 14th week is considered a turning point, because. it is with her that the second trimester of an interesting situation begins. It is a period when you can already relax, because. anomalies and malformations of the fetus are no longer terrible. The baby grows and enlarges so that the ladies who are expecting a second and subsequent child can already feel it. Now he is up to 10 cm tall and weighs up to 40 g. The kid can frown, clench his fists, push off from the peritoneum, swimming up to it. The skeleton continues to strengthen, the child has the appearance of the first ribs.
The 15th week of pregnancy is the time when the cerebral cortex receives its active development. In addition, the development of the endocrine glands of the baby is actively going on, and the sweat glands also receive activity. The digestive system is responsible for the production of the first bile - it is she who will later become the baby's original feces. The kidneys work actively, removing the decay products of vital activity into the amniotic fluid - you should not worry about the fact that the baby swallows his own feces, the waters are constantly updated and remain sterile. The child begins to train the respiratory system - he constantly swallows and spits out the amniotic fluid. It is this simple procedure that allows you to prepare the child's body for the first breath.
The 16th week of pregnancy is characterized by a grown fetus: it is already about 11 cm in height, up to 120 g in weight. Its bones continue to strengthen, and the legs become larger and more uniform. Now he can move his head. All other systems continue to develop according to plan.
For the 17th week of pregnancy, the laying of the rudiments of the permanent teeth of the child is characteristic. Now he is already 13 cm in height and 140 g in weight. If you imagine it from the palm of your hand, then it will already occupy its entire open area. Now he is learning to recognize the voices of his parents - he hears them perfectly and can even respond to emotions. Therefore, doctors recommend expectant mothers to remain calm, because. the child already reacts and adapts to the emotions of the mother.
The 18th week of pregnancy is marked by the active development of the fetus. He already has fully formed legs, arms and fingers with a unique print on the pads. The process of formation of the genital organs is completed. An active process of gaining fat under the skin continues, which should help the child survive in the event of childbirth. The immune system works and produces important substances, such as immunoglobulin and interferon, due to which the baby can even in some sense resist infections and viruses if they enter the uterus. Some mothers can already feel the movement of the baby inside the uterus.
At the 19th week of pregnancy, the fetus gains strength and begins to move more clearly and strongly. The shocks become frequent and strong. In terms of height, he is now 15.3 cm, and in weight up to 250 g. The child begins to develop not only in terms of physiology, but also mentally. During this period, he begins active maturation of the cerebral cortex. This makes him more focused. The broncho-pulmonary system receives special development - a bronchial tree is formed. The sebaceous glands work more actively.
20 weeks for many pregnant ladies is an important period. After all, the child makes itself felt more and more clearly. He now has a fully formed nervous system, respiratory, digestive and hematopoietic organs, nails grow on his fingers. The baby already even reacts to light. The baby during this period reaches 25 cm in length, by weight it reaches 340 g.
Week 21 is characterized by the continued growth of the fetus - it reaches 26.7 cm, the baby is already 360 g in weight. The baby's digestive system continues to develop - it swallows water around itself, thereby training its gastrointestinal tract. Also, the child may begin to move more actively - the mother feels him well and can determine by his movements whether everything is in order with him.
At the 22nd week of pregnancy, the baby is already well developed, now he is learning to control his body. Its weight reaches half a kilogram, it is up to 28 cm in height. At this stage, children are often nursed if childbirth suddenly occurs. The movements that the child makes become more complicated - he does not just suck his finger, but can tilt his head to the sides.
The 23rd week of pregnancy brings amazing discoveries: the baby has noticeably wised up - now his brain has increased by more than 10 times. Now he has a fully formed digestive system - the stomach, liver, and intestines are working. The child can already make up to 60 respiratory movements. Moreover, such activity can often cause hiccups in the fetus - her expectant mother will feel like rhythmic twitching of the abdomen. You can already consider the floor of the crumbs, if he wants to and turns to the ultrasound machine.
At 24 weeks of pregnancy, the baby is getting stronger. Now he is already the same as his mother will see after childbirth, however, a little smaller in size. The baby weighs 600 g, about 30 cm in height. Now he begins to independently produce growth hormone, due to which he begins to increase and gain even more mass. The baby's organs and senses continue to improve, his reflexes improve. His space for movement begins to become smaller, while he still moves quite actively.
25 weeks is the time when the pulmonary system continues to improve. During this period, his alveoli mature. The auricle continues its formation. Now the bone marrow is engaged in the function of hematopoiesis in the fetus - it is from this week that it takes over these functions. The baby plays with the umbilical cord and entertains himself in every possible way, while he has a small margin of time and space.
The formation of the fetus in the weeks of the third trimester is rather monotonous. After all, this is the last finish line before childbirth. At this time, the child can already survive if the birth takes place. Of course, not always with a guarantee of complete health, but modern doctors are quite capable of leaving a crumb weighing about a kilogram.
During the third trimester, every week the amount of subcutaneous fat in the fetus increases - this will allow it to maintain its heat exchange outside the womb until the body gets used to the changing conditions. He also begins to decrease the amount of lubrication on the body, which is already becoming a kind of preparation for childbirth. He is actively growing, adding about 150 g per week. He also grows up - by the time of birth, the growth of the crumbs is 56 cm on average.
All baby systems over the past 14 weeks continue to improve and improve in their work. They grow stronger, acquire new functions that allow the baby to survive after birth. There is less and less room for the baby in the uterus. Somewhere in the region of 30-31 weeks, while there is still an opportunity, the baby can roll over head down, as it should be for a completely normal physiological birth. Ideally, it should no longer roll over.
The baby actively develops the skills he has, plays with the umbilical cord, sucks his fingers, rotates his body, bends over, shakes his head, etc.
At the 7th month, the nervous system continues to improve in the baby - the nerve fibers receive a protective sheath. The number of convolutions and their depth increases markedly. By 32 weeks, the fetus becomes as similar as possible to a standard child - the wrinkles on the skin straighten out, it acquires the necessary proportions. Finally, the formation of the liver and kidneys occurs.
At 8 months, i.e. from 22 to 36 weeks, the baby grows extremely actively - he adds up to 1% of body weight daily. The child has well-developed swallowing, sucking and respiratory reflexes.
At the 9th month of pregnancy (37-40 weeks), the fetus is considered fully mature, and it may well already live outside the womb. In the uterus, he is already cramped, because. it is very large, so its movements slow down somewhat, but it is important to remember that they should not stop completely. He lowers his head and presses in the small pelvis - this signals preparation for childbirth.
Embryo. The developing human body in the period before its birth.
Intrauterine development of a person normally lasts 280 days. During this time, a new completely unique person is formed from two cells that have merged together, able to live separately from the mother's body.
The science that studies the development of the embryo is called embryology. Knowledge about how the human embryo develops is very important for doctors, especially those who work in obstetrics and pediatrics. Ideas about the normal course of embryonic development processes help to accurately and timely note the occurrence of pathologies in developing embryos, look for the causes of infertility and options for solving this problem, create contraceptives, and take measures that will prevent serious pathologies of fetuses and newborns.
The development of a person during his intrauterine life (or embryogenesis) passes through several stages.
In another way, the intrauterine life of a person is divided into three very important periods: fertilization with the formation of one cell (zygote), embryonic and fetal periods.
The embryonic period begins from the second week after fertilization until the end of the eighth week of embryo development (before the end of the tenth week of the obstetric gestation period).
The beginning of the ninth week of intrauterine development of a person (eleventh week obstetric period) marks the beginning of the fetal period (fetal). From this moment on, the developing person is no longer called an embryo, he is called a fetus.
Fertilization is a complex connection (fusion) of two parental sex cells. The process involves one egg and approximately 300 million sperm, of which only one will be the "winner". As a result of this process, the diploid set of chromosomes (that is, 46 chromosomes) is restored. At the time of connection of the parent cells, the sex of the developing person is determined. A new cell is formed - a zygote.
Fertilization in humans occurs in the fallopian tube, in its ampullar part. There are several stages of fertilization:
The egg in this phase of fertilization releases substances that attract sperm. They become capable of fertilization under the influence of a special secret produced in the female genital tract.
It rotates, the acrosomal reaction starts. The result of this is an increase in the permeability of the sperm membrane.
After that, a fertilization membrane forms on the surface of the fertilized egg, it prevents the penetration of other spermatozoa.
On the 7th day after conception, the embryo implants into the endometrium. This process is called implantation, it is very complicated. The duration of embryo implantation is a little less than two days (about 40 hours). Then the actual embryonic period of development begins.
A woman may not yet know about her pregnancy, but a new life is already developing in her body. Many women have suspicions about their pregnancy when menstruation does not come on time. The expectant mother sees only two stripes on the display of a pregnancy test, and the embryo already has the first heartbeats.
This indicates the special importance of the embryonic period of development. The woman's body and the unborn child are very sensitive to environmental fluctuations, the effects of infections, radiation, toxins and drugs during this period.
Knowledge of how the embryo develops day by day and week by week during its intrauterine life helps to understand the timing of the laying of certain organs, with the mechanism for the formation of congenital malformations of embryos, which can even lead to spontaneous abortion. Based on the information obtained, critical (dangerous) periods relating to the development of the human embryo and fetus have been identified. The period from 3 to 8 weeks of embryonic life is designated as critical in human ontogenesis.
The fetal (fetal) period in human ontogenesis starts from the ninth week of embryo development, starting from the moment of fertilization. At the same time, the obstetric gestation period is two weeks longer than the actual period of embryo development. The fertile period ends with the birth of a person. Then comes the neonatal period.
Starting from the 11th week of obstetric gestation, the developing person is called a fetus. It is almost completely formed, all organs are laid in it and there is an active differentiation of tissues. The fetus communicates with the mother's body through the formed placenta.
Although the laying of all organs by this period of fetal development has already been completed, several critical moments of the fetal period differ. So, from the 15th to the 20th week of pregnancy, the brain grows rapidly. And from 20 to 24 weeks of gestation, the functional systems of the body develop, the urogenital apparatus differentiates.
The study of those complex mechanisms of how the human embryo develops after conception continues to the present. The science of embryology describes how an embryo develops day by day in the first week of its life. In the future, embryology describes how the embryo develops week after fertilization (first trimester).
Starting from the second trimester of pregnancy, the description of the development of the embryo by week corresponds to the obstetric gestational age. This means that the gestational age is not counted from the moment of the alleged fertilization, but from the first day of the last menstruation, which is approximately 2 weeks more than the embryonic development period.
Changes in the development of the embryo by day are of particular importance in the first week of embryo development after fertilization. What characterizes the development of the embryo by day at the very beginning of its intrauterine life?
After the nuclei of the parent cells join, a zygote is formed. It begins to divide by mitosis into cells called blastomeres. At first, the zygote divides slowly, then faster.
Blastomeres are formed of two types: "dark" and "light". "Light" cells line up in one layer around the "dark" ones, they form the trophoblast. It is the connecting link of the embryo with the mother's body, provides it with nutrition. From the "dark" blastomeres, the embryoblast begins its formation - the precursor of the body of the human embryo, as well as its extra-embryonic organs.
After the formation of the zygote, a dense accumulation of blastomeres forms a morula. On the 3-4th day, a blastocyst is formed - a vesicle with a cavity. Within three days, the blastocyst moves through the fallopian tube directly into the uterine cavity. At this time, embryo- and trophoblast cells continue their differentiation. The size of the embryo in this period is up to 0.2 mm.
The free blastocyst stays in the uterus for two days. The cells of the blastocyst trophoblast provide the embryo with nutrients due to the decay products of the mother's tissues. Embryoblast cells are located in a knot at one of the blastocyst poles, which is attached to the trophoblast from the inside. The embryo is preparing to attach to the wall of the uterus.
On the 7th day after conception, the embryo is implanted in the mucous membrane of the uterine cavity, that is, it is introduced into it. Embryo implantation takes place in two stages:
The trophoblast has the ability to secrete enzymes that promote attachment of the embryo to the inner layer of the uterus. This is followed by destruction of the fertilization membrane.
From the second week, the actual embryonic period of development starts. It continues until the end of the eighth week of development (until the end of the tenth week of obstetric gestation). The human embryo does not stop its development even for a second. For convenience and ease of understanding, this period of human development is divided into weeks. How does the embryo develop week by week during pregnancy?
An amniotic vesicle is formed from a part of the blastocyst cells. This happens by the 8th day of embryo development. By day 11, the formation of the chorion occurs. This villous membrane of the embryo is the precursor of the placenta. Up to 12 days, the process of implantation of the embryo continues, which began a few days earlier, and the process of gastrulation starts.
Gastrulation continues from day 13. This is a very complex process in which the tissues of the embryo grow and differentiate, resulting in the formation of germ layers: ecto-, meso-, and endoderm. From part of the cells of the blastocyst, a primary strip is formed, from which the head process of the embryo is formed. From it begins to develop the chord of the embryo (the future spinal column).
Vessels and blood cells begin to form in the embryo (hematopoiesis). In addition, there is a growth of blood vessels in the region of the chorion. The formation of the first blood cells takes place in the yolk sac. At this time, the embryo is connected by a stalk to the placenta, which began its formation.
After 15 days from the day of conception, the embryo reaches a size of 0.4 mm. It forms a chord, a perichordal plate. The embryo itself has a three-layer structure.
The embryo in the period of 17-19 days of its development has a length of about 1-1.5 mm. It has the shape of a pear with an extended head end. From the thickening of the ectoderm, the neural plate is formed, and from it - the neural groove. The tissues of the nervous system of the embryo originate from the neural groove. Vessels and blood cells develop further.
At the age of 19-21 days, the human embryo is elongated. The head end of the embryo in this period is wider than the caudal end. The seals of the mesoderm are determined. Secondary chorionic villi are forming. In addition to hematopoietic cells, endothelial cells are determined in the yolk sac, they will subsequently become the internal lining of arteries and veins.
By the end of the 3rd week of embryo development, the heart is laid. It looks like two tubes, while separate. A probud is formed, but it is soon reduced.
The size of the embryo at the beginning of the 4th week of its development varies from 1.5 to 2.5 mm, but towards the end of this week it reaches 5 mm in length. The embryo in this period is shaped like the letter "C". First, the neural groove is formed, which then closes into the neural tube. Nerve cells, rudiments of ears and eyes are already present in the head of the embryo.
The previously separated tubes, which were the precursors of the heart, are closed. You can register the first heartbeats, blood flow begins in different parts of the body of the embryo. In the middle of the 4th week of intrauterine life, partitions and valves are laid in the heart of the embryo.
The epithelial tissue of the digestive tube gives rise to the digestive organs (liver, pancreas), and the trachea, esophagus and lungs begin to form from the epithelial tissue of the pharyngeal intestine.
By the end of the 4th week, the embryo is curved in a semicircle, located in the amniotic vesicle. The rudiments of the arms are formed, the laying of the legs is noted. Skin epithelium is being formed. Bones and muscles begin to form.
There is a differentiation of the head part of the neural tube, three cerebral vesicles are formed. The auditory vesicle is formed, the lens of the eye is formed. You can find the primary oral cavity (bay) and the rudiment of the tongue. The formation of the thyroid gland is underway, the respiratory and digestive organs are actively developing, the primary kidneys are being laid.
The umbilical cord is formed, it connects the vessels of the placenta and the liver, the location of which at this time is in the head of the embryo.
The size of the embryo at the 5th week from the day of fertilization is 5-7 mm. It is folded in an arcuate manner, it has a noticeable cervical bend. The arms lengthen, the formation of the hands and the innervation of the upper limbs begin.
There is an intensive growth of the heart and brain, which is divided into parts: anterior, posterior and middle. There is a differentiation of the spinal cord, there is an active development and growth of the anterior pituitary gland, the lens of the eye is being improved.
The esophagus becomes clearly visible, which gradually separates from the trachea. On both sides of it are the lungs. The heart has four chambers, its valves are formed. A permanent kidney and bladder are being formed.
At 6 weeks, the embryo measures between 7 and 13 mm in length. In the first days of the 6th week, the primary face is outlined in the embryo, the outer ear is formed. The eyelids of the embryo close, the nasal fossae are determined. The brain of the embryo increases, the laying of the spinal nodes is underway. The deepening of the oral cavity grows in the direction of the intestinal tube. The digestive tube increases in length, the growth of the esophagus is noted. The kidneys are progressively developing. Segments are defined in the arms of the embryo. The feet and their innervation begin to form. Throughout the week, the embryo develops rapidly, the face and sensory organs noticeably change.
An embryo at 6 weeks is different in that its back gradually straightens, ossification of the skeleton is initiated. The muscles of the face and lower jaw appear. The auricles are determined, the pituitary gland is formed. In the eyes, pigment is formed, the eyelids grow together. There is a bookmark of the rudiments of teeth, olfactory bulbs. The embryo at 6 weeks has well-formed arms, although the hands are not yet fully developed.
The development of the respiratory organs is in full swing. The heart has 4 chambers, and the pulmonary artery separates from the aorta. The diaphragm is being formed. The intestine of the embryo is sent to the umbilical cord, which is called the physiological hernia of the embryo. The liver and pancreas develop. The sex glands are populated by germ cells, which are still primary. The development of the genital organs begins. The kidneys produce the first urine.
The size of an embryo at the 7th week of its intrauterine life is from 17 to 28 mm. Its shape resembles an arc. The tissues of the skull and face are being formed. The lower jaw is well visualized, while the upper jaw is not yet clearly defined. Fingers are formed on the hands, segments are distinguishable on the legs, the foot is developing.
There are clearly 2 hemispheres in the brain, the development of the hindbrain starts. In the abdominal cavity, the mesentery is clearly visible, in which arteries, veins, nerves, and lymphatic vessels are determined. There is an elongation of the ureters, which are directed from the kidneys to the laying of the bladder.
At the 8th week of its development, the embryo is approximately 25 to 40 mm. By the beginning of the 8th week, the head of the embryo straightens. He has well developed eyes, which are still located on the sides of the head. There is a low location of the ears, formed nostrils. Convolutions are visible in the hemispheres of the brain. The structures of the inner ear are being formed.
The skeleton is actively developing, the back is lengthening, and skeletal muscles are developing. Arms bent at the elbows are crossed on the stomach. The places of large joints are indicated on the legs, the toes are distinguished, although there are still membranes between them.
At the 8th week after fertilization, the embryo begins to make the first movements, which are still involuntary. In the heart, a septum develops between the atria. By the end of week 8, the critical period of heart formation is completed.
The tongue is almost formed, taste buds and teeth are developing. The bones of the hard palate merge. The intestine, which previously entered the umbilical cord, returns to the abdominal cavity. The genital organs, both external and internal, are actively developing. The sex of the child becomes discernible. The anal membrane is perforated. Tail degeneration occurs.
With the introduction of ultrasound diagnostics (ultrasound) into medical practice, future parents have the opportunity to look at their child long before his birth. According to pregnancy management protocols, the first ultrasound is done at an obstetric gestational age of 10-14 weeks (8-12 weeks of embryonic development). This study coincides with the sampling of venous blood from the expectant mother for analysis.
All these activities are called screening during pregnancy.
To see the embryo on an ultrasound before this time, there must be indications. For example, a suspicion of an ectopic pregnancy, preparation for an abortion, the appearance of some pathological symptoms in a woman, a suspicion of a miscarriage.
Some do an ultrasound of the embryo just out of curiosity, but such a risk is not justified. Currently, there is not enough information about how safe ultrasound of the embryo is and how many times it can be done during the period of bearing a child.
What does an embryo look like on an ultrasound?
At 3-4 weeks of embryonic development, the embryo is still too small to be able to clearly see parts of the body or emerging malformations. During this period, the expectant mother will see only a bright spot and the first heartbeats on the monitor. But it is safe to say whether the embryo is located in the uterus.
By the end of the 7th week, on the ultrasound of the embryo, one can distinguish the head, torso, limbs, and the formed umbilical cord. The embryo itself has a characteristic curved shape.
By the end of the 8th week of embryonic development, according to ultrasound, you can already get a lot of information about the embryo, see some malformations, if any. For the mother, on the screen of the ultrasound monitor, parts of the body of the embryo, some organs, and active heartbeats become noticeable.
To make a high-quality ultrasound of the embryo, transvaginal (through the vagina) and transabdominal (through the anterior abdominal wall) scanning are used.
More than 50 years ago, people first saw the embryo in the photo. These unique photographs, reflecting human development at different stages of pregnancy, starting from the moment of fertilization, were taken by Swedish photographer Lennart Nilsson. To capture the embryo in the photo, he used modern photographic equipment, a light guide and a cystoscope. Thanks to him, the whole world saw such a mysterious intrauterine life of a person. These photos of embryos are still very popular, they play a big role in the fight against abortion in early pregnancy at the request of women.
Modern parents can see their child during an ultrasound examination. Ultrasound equipment allows you to take a photo of the embryo, obtaining a two-dimensional or three-dimensional image.
There is a huge number of infertile marriages in our country. There are more than 15% of them. In total, in Russia there are officially more than 5 million married couples whose marriage is recognized as infertile. Moreover, both female and male infertility is growing. More than 2.5 million couples require assisted reproductive technologies.
The basis of assisted reproductive technologies is the classical method of in vitro fertilization (IVF) and embryo transfer (ET) into the uterus.
In vitro fertilization (IVF) is a method of artificial insemination of eggs taken from women with male sperm, which is then centrifuged and processed in a nutrient medium. Oocytes (eggs) are also cultured on nutrient media. Subsequently, the resulting embryos are transferred into the uterus.
In most cases, during in vitro fertilization, the germ cells of the spouses are used. Donation of oocytes (oocytes) and embryos is used when it is impossible to get a woman's own genitals or when they are inferior. Sperm donation is applied at the request of a woman if she does not have a spouse, as well as if the spouse has sperm that are not capable of fertilization.
There are the following types of IVF:
The egg is fertilized by sperm outside the female body, then the embryo is implanted in the uterus.
A special feature is that the embryo during IVF is formed as a result of the fusion of the egg and sperm, which was introduced under the shell of the mother cell using a special microneedle. The method is used for various qualitative and quantitative pathologies of male germ cells.
There are situations when, after several unsuccessful IVF attempts, it is possible to achieve pregnancy only by using the ICSI method.
In addition, surrogacy is highlighted, in which the embryo after IVF develops in the uterus of a female volunteer. After birth, the child is passed on to its genetic parents.
There are the following indications for in vitro fertilization:
The list of contraindications for IVF and embryo transfer is very wide:
At the preparatory stage for IVF, spouses undergo numerous examinations and pass various tests in order to identify indications and contraindications for the procedure. Couples whose spouses are over 35 years old must consult a geneticist.
After the couple is prepared for the IVF procedure, she will have to go through the following steps:
The biological material for obtaining an embryo is eggs and sperm.
This procedure is done under general anesthesia under sterile conditions. When receiving biological material, a woman is placed in a conventional gynecological chair. The oocyte retrieval process is monitored by ultrasound. The cells are harvested by puncturing the ovarian follicles with a special needle inserted through the vagina. If it is not possible to obtain eggs in this way, then egg collection is carried out using laparoscopy.
The sperm is collected on the same day as the eggs. It is possible to obtain sperm through masturbation or coitus interruptus (using a condom without lubrication and spermicides). In the presence of ejaculatory disorders in a man, spermatozoa are obtained by puncture of the epididymis.
After the sampling procedure, germ cells enter the embryological laboratory, where they are cleaned of impurities. Sometimes the in vitro fertilization procedure is carried out immediately (no later than 6 hours after receiving the material). In other cases, the biological material is frozen. Freezing practically does not affect the viability of germ cells, but it saves time during subsequent IVF attempts, if the first of them are unsuccessful.
For fertilization, germ cells are placed in special containers with nutrient media. The containers are placed in an incubator where the conditions are close to natural. After a few hours, the germ cells merge together. If this does not happen, then the sperm is injected artificially into the cytoplasm of the egg.
After the procedure, the fertilized eggs are monitored. Those that divide well can be used for IVF. Excess fertilized eggs can be frozen (cryopreservation) and used in repeated IVF attempts (if necessary).
An embryo after conception in a natural way does not differ from an embryo after IVF in its structure, physiology and stages of further development. However, germ cells that are used for IVF are more often defective compared to those with natural conception. Including for this reason, after IVF, the risk of congenital pathologies and chromosomal abnormalities in the unborn child is higher. Some signs of these problems can be noted in the embryo by ultrasound or by the results of pre-implantation diagnosis.
Pre-implantation diagnostics of embryos during IVF is carried out in order to obtain information about whether the unborn child has serious genetic pathologies. This is done before the time is right for the implantation of the embryos.
The use of this method of examination of human embryos has led to the fact that the number of spontaneous abortions has decreased to 13% after the onset of pregnancy as a result of IVF in those couples where one of the parents is a carrier of genes that cause chromosomal abnormalities compared to couples with similar problems, but who have not used the services of pre-implantation diagnosis.
Detection of chromosomal abnormalities in embryos before implanting them into the uterus not only allows you to get healthy offspring, but also reduce the number of IVF attempts, reduce the risk of spontaneous abortion.
There are recommendations according to which you should not plant more than four embryos in the uterus. First, multiple pregnancy is fraught with complications. Secondly, the reduction of extra embryos is also not a harmless procedure. In our country, as a rule, two embryos are transplanted into the uterus.
On the day when the embryo is transferred into the uterus, the period of its development reaches approximately 3-5 days. The stage of development of the embryo at this time is the blastocyst. Studies have been conducted indicating that it is at the blastocyst stage that the embryo in the uterus takes root best. The embryo already has a trophoblast, which is needed for implantation.
Less commonly, embryo transfer is carried out on the third or second day of embryonic life, or 7-8 days after fertilization. The decision is made individually in each case. The term of embryo transfer depends on how many eggs were fertilized, and how many of them continued their further division.
On the 4th day of its existence, the embryo has dimensions of about 0.14 mm, on day 6 - 0.2 mm, by the end of 1 week of life - about 0.3 mm.
During the transfer of embryos into the uterus, the expectant mother is on the gynecological chair. The procedure requires compliance with the same sterility as in any other operation.
First you need to insert a speculum into the vagina. Then a thin flexible catheter is inserted into the uterus through the cervical canal, through which the embryos are transferred.
Women preparing for an in vitro fertilization procedure want to know in advance how they will feel during the embryo transfer.
During the embryo transfer procedure, the woman is conscious. Feelings during embryo transfer are comparable to those during a regular gynecological examination (introduction of mirrors). Some describe the sensation of embryo transfer as mild discomfort.
To avoid discomfort during embryo transfer, a woman is advised to relax, tune in to a good outcome of the procedure, and there is no need to strain the abdominal muscles.
At the end of the procedure, you need to rest and lie down for a couple of hours. After IVF, you can return home from the clinic on the same day. It is desirable that the woman had an escort. At home, you need to relax and not worry.
The procedure for replanting embryos does not guarantee that pregnancy will occur. Whether the IVF process was effective can be judged after the implantation of the embryos is completed.
Attachment of the embryo after IVF usually occurs 7-10 days after the day of ovulation (2-3 days immediately after IVF).
On the day of implantation of the embryo into the endometrium, a slight bloody discharge from the vagina may occur. They are due to the fact that the implantation of embryos leads to damage to the mucous layer of the uterus.
On the days of the supposed implantation of the embryo, some women describe some symptoms in themselves: a slight soreness in the lower abdomen, drowsiness, weakness, dizziness, a metallic taste in the mouth, a slight increase in temperature. Whether these symptoms are specifically related to embryo implantation is not known.
In order for the day of embryo implantation to be successful, a woman needs to adhere to some rules: eat rationally, limit stress, not lift weights, refrain from taking a bath, wear loose clothing. Compliance with medical recommendations on diet, rest and physical activity allows you to achieve good results on the day of embryo implantation.
A reliable sign that the implantation of the embryos has been successful will be an increase in the content of human chorionic gonadotropin (hCG) in the mother's bloodstream.
Usually, during IVF, several embryos develop. Two embryos are usually transferred into the uterus. If it turns out that more than three embryos are developing in the uterus, then an operation is indicated for the reduction of embryos from the uterus (removal of excess ones). This forced measure is necessary for a normal pregnancy with twins or triplets.
The method of embryo reduction in IVF has a good reason, it is constantly being improved, and allows a couple to get healthy offspring. This is due to the fact that the bearing of three or more fetuses in the uterus threatens with miscarriage and the birth of very premature babies.
Removal of excess embryos was initially carried out through the cervix. The underlying ovum was removed in the first trimester of pregnancy. However, this method of removing a human embryo turned out to be very traumatic, followed by many complications.
Currently, other methods of embryo reduction after IVF are used: transvaginal (through the posterior fornix of the vagina) and transabdominal (through the anterior abdominal wall). The intervention is carried out under the control of special equipment. The principle of the procedure is that a long needle is inserted into the uterine cavity, its tip is brought to the chest of the embryo to be reduced. Then, with the help of a needle, the organs of the chest of the embryo are destroyed until the heart stops working.
The course of pregnancy after in vitro fertilization has its own characteristics.
After IVF, the birth of children is possible both through the natural birth canal and by caesarean section. Considering the high risk of multiple pregnancy, the presence of various concomitant pathologies in the mother, caesarean section after IVF is done to most women. Other factors that may affect the choice of method of delivery are: the age of the mother, the duration of the period of infertility, preeclampsia during pregnancy, the condition of the fetus. Be sure to take into account whether the woman had childbirth before, and in what way the children were born.
By itself, the process of childbirth or caesarean section after in vitro fertilization is no different from that during the conception of an embryo in a natural way.
Like any intervention in the human body, IVF has its own complications:
The effectiveness of the in vitro fertilization procedure varies from country to country. Not all pregnancies that occur after the implantation of embryos in the uterus develop successfully and end in childbirth. Many pregnancies are terminated in the first trimester. On average, only every fourth woman has a baby after IVF.
