Main article: Human body
Genetics
Main article: Genetics
Gynecology
Main article: Gynecology
Sperm, uterus, egg, conception
How Sperm Understand Where to Move Them
Egg chooses which sperm to let in
Previously, it was believed that in the process of fertilization, the egg does not show itself in any way, only expects a sperm running towards it.
But studies of the early 2020s show that, despite its size, the egg is quite active and it is it that decides which specific sperm will penetrate it to merge genetic materials.
The task of the egg is to select a sperm with undisturbed DNA.
How a sperm enters an egg
For successful conception, at least 10 million sperm must enter the uterus. Almost all of them meet with an egg, but only one penetrates inside. The fact is that after meeting an egg, sperm still need to overcome certain barriers.
Directly, to merge with the egg, the sperm must pass two shells: a radiant crown and a shiny shell. To overcome the radiant crown - the layer of cells surrounding the egg cell, the sperm uses a special enzyme located on the surface of the head and splitting structures connecting the cells of the radiant crown.
One sperm is incapable of destroying the radiant crown, requiring exposure to 300 sperm to loosen and disperse the cells of the radiant crown. The sperm that first reaches the shiny membrane is most likely to undergo fertilization. If it turns out to be defective, then fertilization will not take place.
Thus, 10 million male germ cells get to the egg, but only one penetrates inside - the most lucky.
What depends on the sex of the child
The baby's sex is determined as soon as the egg is fertilized. In humans, the sex is determined by sperm, not the egg.
All normal human eggs contain an X chromosome. Spermatozoa may contain either the X- or Y-chromosome.
If the sperm contains a Y chromosome, then the infant will be male, and if X - then female.
Days most likely to be pregnant
The most likely days for pregnancy are 10 days around the day of ovulation. With a 28-day cycle, these will be from the 9th to the 19th days of the cycle. The countdown is from the 1st day of menstruation.
Infertility and IVF
Main article: Infertility
Reproductive health
Main article: Reproductive health
Fertilization
2025: Discovery: Amazing DNA self-organization takes place in the first hours after fertilization
At the end of April 2025, an international group of scientists led by the German research center Helmholtz Munich released the results of work that shed light on the processes of spatial organization of genetic material in the cell nucleus within the first hours after fertilization.
When the egg and sperm merge, complex DNA reorganization begins in the nucleus. Epigenetics plays a crucial role in this process by regulating gene activity through chemical modifications of DNA and related proteins. Experts came to the conclusion that the main regulators do not control the self-organization of DNA: instead, multiple other mechanisms are used that allow embryos to correct errors in the initial organization of the nucleus.
Scientists also found that gene activity is not determined by strictly nuclear positioning. That is, the position of genes in the nucleus does not always correlate with their activity.
The study participants made another important discovery. It turned out that embryos can independently correct violations in a nuclear organization even after the first division of a fertilized egg. If such an organization has been disrupted before the first division, it can recover during the second cell cycle. This suggests that early embryos are not only resilient, but also possess error compensation mechanisms in their original nuclear organization. The researchers found that this process is regulated by epigenetic tags inherited from the maternal egg. If maternal signals are disrupted, the embryo may activate alternative epigenetic programs to eventually restore proper nuclear organization and prevent developmental defects.[1]
How the internal organs of the mother are displaced during pregnancy
Many pregnancy symptoms occur due to hormonal changes. However, many of them also arise as a result of the fact that the child begins to occupy more and more space inside the mother's body.
The animation shows how a growing child compresses the lungs, bladder and intestines of the mother.
Fetal formation
While the fetus is in the womb, every minute is formed to 250,000 new cells, and each a second creates 1.8 million new connections.
About half will be lost later, only fortified will be saved and used
Fetal development by week
Day 6
Day 23: The Heart Starts Working
On about the 23rd day of pregnancy, the heart begins to work for the future baby.
At this gestation point, the embryo's heart is slightly smaller than the rice grain.
Embryo Development Week 4
The child is formed head. Heart, handles and legs form.
Blood circulation is established, which is visible on ultrasound. The brain and spine form.
Day 28: Nerve tube splits into three primary bubbles that will become the brain
The middle brain is only about 2 centimeters long and is located at the very end of the cerebral column. This is the smallest part of the pillar, but it plays a decisive role in the embryonic development of the future person.
On about the twenty-eighth day of intrauterine embryo development, the neural tube splits into three primary bubbles, which will later become the brain.
These are the diamond brain, the midbrain and the anterior brain. After a few weeks, the secondary brain, or posterior brain, subsequently developing into the bridge and cerebellum, and the oblong brain separate from the midbrain.
And from the forebrain, the cerebral hemispheres covered with the cortex and the intermediate brain (hypothalamus, thalamus, etc.) are formed. And the middle brain is really in the middle and remains the middle brain.
Week 5: The beginning of intensive formation of internal organs
From the 5th to the 16th week of intrauterine development, the stage of intensive formation of all internal organs and systems of the future person lasts.
At this stage of development, the embryo has a tail and the smallest grooves in the neck, resembling the gills of an embryonic fish.
Flexor folds on the palms, the pattern of which is different in each person, form by the third month of fetal development in the womb and never change.
And only after this time does the fruit take on the look that we used to imagine.
The appearance of eyelashes in humans occurs in the womb at 15-16 weeks.
Bending features, number of rows, and length are determined by genetic predisposition.
In the 21st week of pregnancy, you can watch a baby "cry" in the womb. He makes the same movements as when crying, but does not make sounds. By the third trimester of pregnancy (weeks 26-40), the child develops vocal cords, but amniotic fluid still does not allow him to produce sounds.
Fingerprints
The fetus acquires fingerprints at the age of three months.
Even in the early stages of development, fruits have one of the most unique human features - fingerprints. In the 6-13 weeks of development, they are already taking on a clear shape. These prints will not change throughout life and will be one of the last things that will disappear after death.
How a person's face develops in the womb
The face begins to form from tubercles called visceral arches. They form, starting from the outside inwards, from the sides to the middle. In the process of transformation, which lasts 4.5 months of pregnancy, the baby's face will gradually acquire nostrils, eyes, eyelids, lips, and so on.
Tail
Human embryos in the early stages of development have a noticeable tail.
However, even during embryogenesis, the parts of the embryo surrounding it overtake it in growth, and it ceases to protrude above the surface of the body.
Although as a rare deviation in development, a person may develop a short tail.
Fetal behavior in the womb
In the uterus, the fruit sleeps most of the time.
Due to low oxygen levels and placental sedatives, it is awake for no more than 10% of the total time. The rest of the time, he alternates phases of calm and active sleep.
At the same time, the child in the stomach of the mother moves almost constantly.
At the 20th week of pregnancy, the fetus makes about 200 movements per day, and between the 28th and 32nd weeks, the number of movements reaches 600 per day.
A fight between twins in the womb, recorded during an ultrasound examination.
A pregnant woman does not feel all the movements of the fetus, but only a small part of them. So, after 28 weeks, the frequency of movement of the fetus according to the woman's sensations is usually from 4 to 8 times per hour, with the exception of periods of fetal sleep (3-4 hours in a row). In the third trimester, a pregnant woman may notice that the baby has certain sleep and wake cycles. Children are usually most active from 7 p.m. to 4 a.m., and the "rest" period occurs more often from 4 a.m. to 9 a.m.
Of course, the movements of the fetus depend on the mood of the mother, if the mother is worried or happy, the baby can move more actively, or vice versa, calm down. The fact is that when mom rejoices, the amount of joy hormones in her body significantly increases - endorphins, which regulate the work of the heart and blood vessels, including the vessels of the placenta. During stress or pronounced negative emotions, biologically active substances are also produced - stress hormones, they also act on the work of the heart and blood vessels. It is thanks to this biological interaction between the organisms of mom and baby that the fetus feels the condition of the mother.
When it got too boring in the womb.
When the expectant mother rests, the baby usually becomes more active, if the pregnant woman is active, busy with any work, the child most often subsides. The movement also changes depending on the fullness of the expectant mother. Usually the baby begins to move actively after the mother eats, especially something sweet. At the same time, the level of glucose in the blood increases sharply, which makes the fetus be more active.
In the video below, the baby in the womb warms up before being born.
2025
In Russia, developed and began to use an implant that helps women without cervix to give birth to children
Russian scientists have created a unique medical implant made of cermet mesh, which allows women to successfully carry pregnancies and give birth to healthy children after removing the cervix. Thanks to the new technology, 28 babies were born, including 17 boys and 11 girls. The results of the application of innovative development became known on September 22, 2025. Read more here.
Why pregnant women feel sick. Scientific explanation
At the end of September 2025, American specialists from the University of California, Los Angeles (UCLA) published the results of the study, indicating the presence of a connection between the symptoms of "morning nausea" and the complex natural response of the body to biological and physical changes during pregnancy.
Up to health care USA 80% of mothers in early pregnancy experience nausea, vomiting and aversion to certain foods and smells, according to the National Institutes. Although these symptoms are uncomfortable, they are not usually a sign of a woman's health problems or a developing fetus - instead, they indicate a special state of the body inherent only in pregnant women.
 | During pregnancy, a woman's immune system faces a difficult task: she needs to protect both the mother and the fetus from infections, but not harm the child, whose genetic component is half foreign, since it is received from her father, says UCLA professor Molly Fox. |  |
Researchers believe that the delicate balance that provides protection to the mother and fetus is achieved through a unique mechanism associated with the work of cytokines - proteins that regulate the work of the immune system. They, in particular, control inflammatory responses. Scientists say that in pregnancy, a special combination of such reactions, on the one hand, prevents the rejection of the fetus by the mother's body, and, on the other hand, encourages a woman to avoid potentially harmful products, provoking nausea.
In other words, nausea, vomiting or aversion to food or smells are not signs that something is wrong with the mother or fetus. On the contrary, it reflects the body's healthy and necessary immune response.[2]
Pre-conception CT scan causes complications for pregnant women - fetal loss and congenital malformations
In early September 2025, Canadian specialists from the Jewish General Hospital in Montreal released the results of a study indicating that computed tomography before the conception of a child causes complications in subsequent pregnancy. Among the possible negative consequences are fetal loss and congenital malformations. Read more here.
China introduced the first robot capable of carrying a child instead of a woman
In mid-August 2025, the Chinese company Kaiwa Technology, based in Guangzhou, announced the development of the first robot capable of carrying a child instead of a woman. The appearance of such a machine provoked a contradictory reaction from the public. Read more here
Why do specific women have a chance of giving birth to a boy or girl not 50 to 50. Scientific explanation
Scientists have found that the probability of giving birth to a boy or girl in individual women does not correspond to the generally accepted ratio of 50 to 50, but depends on the individual characteristics of the mother. Harvard University researchers have identified a key role for a woman's age at the first birth in shaping the propensity to have babies of a particular sex. The results of the work were published on July 21, 2025.
The scientific group analyzed the medical data of 58 thousand American mothers to study the factors affecting the sex of newborns. The study aimed to explain numerous cases in which families give birth exclusively to boys or exclusively to girls.
Traditional biological theory states that the sex of a child is determined by a random combination of sex chromosomes. The egg always contains the X chromosome, while the sperm can carry either the X chromosome for the girl or the Y chromosome for the boy. The probability of both options is assumed to be equal.
The study authors analyzed eight potential influences on offspring sex. The list included female growth, body mass index, race, hair color, blood type, biological rhythms of activity, age of onset of menstruation and age at birth of the first child.
Statistical analysis showed that only the age of the mother at the first birth has a significant effect on the probability of having children of the same sex. The remaining seven factors showed no correlation with neonatal gender.
Women who became mothers after the age of 28 showed a 43% chance of having all children of the same sex. In women who gave birth to their first child under 23, this figure was 34%. The difference of nine percentage points indicates a significant influence of the age factor.
One of the co-authors of the study noted that the sex of newborns has always attracted the attention of biologists, demographers, statisticians and sociologists. The analysis showed that the sex distribution did not fit into a simple binary scheme of equal probability.[3]
Hormones
Oxytocin
Main article: Oxytocin
The content of oxytocin in the brain increases sharply when breastfeeding an infant - both in the mother's brain and in the baby's brain.
This hormone provides a number of important physiological functions: from pregnancy, uterine contractions during childbirth to the production of breast milk.
Effects of maternal health on child health
Extreme climatic conditions may affect infant brain in utero
A study published in PLOS One in 2025 shows that climate disasters can change the brains of children even before they are born.
Scientists examined 34 children, of which 11 were in the womb during the Sandy super-storm (2012, New York). When the children turned ~ 8 years old, scans showed an increase in the basal ganglia of the brain in those who were in the womb during the storm - an average of 6%.
Basal ganglia are associated with emotional regulation, movement, behavior, and their dysfunctions are often observed in depression and autism.
In a group where pregnant women faced not only a storm, but also extreme heat, the changes in the brain were even stronger.
This emphasizes the importance of protecting pregnant women from climate stressors (heat, evacuation, power outages). Need to inform future parents of the risks.
The study is small but significant. In 2025, the team conducts an expanded analysis with 80 people, but the already published data is designed to warn society.
Development of schizophrenia linked to maternal vitamin D levels
On May 24, 2023, Australian neuroscientists from the University of Queensland published the results of a study suggesting that the development of schizophrenia is associated with maternal vitamin D levels. Read more here.
Pregnant women's caffeine intake affects children's growth
In early November 2022, the American College of Obstetricians and Gynecologists recommends that pregnant women limit their caffeine intake to 200 mg per day. In women who received at least moderate amounts of caffeine during the first trimester of pregnancy, babies of slightly smaller average height are born, and by the age of eight, the difference can reach a couple of centimeters.
In animal studies, this led to a change in normal growth patterns. Moreover, excess caffeine could also lead to increased fetal insulin sensitivity, potentially having long-term effects on normal growth, scientists said. The study takes into account all caffeine, including decaffeinated foods and foods that may contain caffeine. This list includes chocolate, tea, energy drinks and soda.
In the course of the study, scientists analyzed the concentration of caffeine and the product of its decay, paraxanthine, in blood samples of more than 2.4 thousand pregnant women who participated in two studies. The scientists looked for a correlation between future moms' caffeine intake and height, weight, body mass index and obesity risk.
Children of women with low caffeine intake during pregnancy were slightly shorter than their peers born to women who did not consume caffeine during pregnancy. The difference in height increased between the ages of 4 and 8, the study showed. The analysis took into account several other factors that may have influenced the baby's height, including maternal height, pre-pregnancy weight, and smoking status. The researchers found only an association between caffeine intake and childhood growth, not a causal relationship.
The study's lead author Jessica Gleeson explains this impact by the fact that caffeine is able to pass from mother to fetus, which is not yet able to dispose of it in the way that the adult body does. As a result, caffeine can accumulate in embryo tissues and disrupt their normal response to growth hormones. However, according to Jessica Gleason, so far this is only an assumption: the study itself does not demonstrate either mechanisms or a causal relationship, but only indicates a correlation between moderate and large amounts of caffeine in the blood of pregnant women and the growth of babies born to them.[4]
Maternal microflora affects the development of the baby's brain and immune system
In 2019, the claim that the development of a child in the womb occurs in sterile conditions was refuted.
Studies conducted in Austria confirm that the first contact of the child with bacteria occurs in the womb. The discovery was made following the analysis of samples of amniotic fluid, which enveloped the fetus. All samples taken contained traces of bacterial DNA. This cover forms a huge value for medicine. After all, the peculiarities of the mother's microflora can directly affect the development of the child's brain and immune system.
Effect of alcohol on foetal neurons
In moderate doses, alcohol does not kill adult neurons, but it can have a strong effect on developing nerve cells.
Since almost all neurons form and move to their places before birth, the fetal brain is very susceptible to alcohol.
Alcohol can kill newly born neurons, hinder their birth, and prevent them from moving from their birthplace to their final residence.
Even a short-term increase in blood alcohol levels can be enough for some fetal nerve cells to die.
Milk pumps
Main article: Breast pumps
Maternity leave
Main article: Maternity leave
Pregnancy TECont
Main article: Monitoring of pregnant women
Childbirth acceptance training
2025: Robots in labor appeared in Russian medical universities to teach students who moan, cough and complain about their well-being. They cost millions of rubles
Altai State Medical University announced the purchase of high-tech simulation equipment worth ₽5,4 million to prepare students and residents for emergency medical care. Interactive dummies of a woman in labor and a newborn are able to reproduce human speech, including complaints about well-being, moans, coughs and other sounds that mimic the behavior of real patients. The tender for the supply of simulators was posted on the public procurement portal on September 4, 2025. Read more here.
Diseases during pregnancy
2021
Ministry of Health: In Russia, the number of births from mothers with HIV is growing by 13-14 thousand per year
On December 20, 2021, it became known about the annual increase in the number of children born from HIV-infected mothers in the Russian Federation by 13-14 thousand people. With such dynamics, in 5-6 years, the total number may exceed 300 thousand, said Ministry of Health Russia Yevgeny Voronin, chief freelance children's specialist in HIV infection. More. here
In Russia, maternal mortality from COVID-19 increased by 3 times
In 2021, the mortality rate of pregnant women and women who gave birth from coronavirus COVID-19 tripled compared to 2020. This data was published in early December 2021 by the chief freelance specialist Ministry of Health Russia in obstetrics, Professor Roman Shmakov. More. here
The number of pregnant women who died from COVID-19 in Russia reached 149 women
On June 29, 2021, it became known about the number of pregnant women in Russia who died from the coronavirus COVID-19. Due to the consequences associated with this infection, 149 women in the situation died. Read more here.
Operations during pregnancy
Main article: Operations during pregnancy
Childbirth
Why contractions begin
When the fetus in the uterus notes that the mother can no longer provide the growing organism with sufficient nutrition, the stress axis is activated in the fetal hypothalamus.
Adrenocorticotropic hormone (ACTH) stimulates adrenal cortisol production, which reduces progesterone exposure from the placenta and increases estrogen production. The uterus becomes more sensitive to oxytocin, this stimulates contractions, and labor begins.
Biomechanism of childbirth
C-section
Main article: Caesarean section
2025: Device for instant stop of postpartum bleeding released
Read more here.
2024: Decrease in the number of births in Moscow by 6% to 110 thousand
The number of births in Moscow medical institutions decreased from 118 thousand in 2020 to 110 thousand in 2024, which is a decrease of 6% over a five-year period. The demographic indicators of the capital demonstrate a steady negative dynamics associated with a change in the reproductive behavior of residents of the metropolis. This is evidenced by data from the analytical company BusinesStat, released in September 2025. Read more here
Maternity hospitals in Russia
Main article: Roddoms in Russia
Preterm birth
Main article: Preterm birth
Twins
2021
South African woman gives birth to 10 live children at the same time
In early May 2021, a resident of YUARGosiame Sithoul set a new world record by giving birth to ten children at once, thereby breaking the maximum of 25-year-old Halima Cisse with Mali, who had previously given birth to nine babies at the same time. Read more here.
Mali woman gives birth to 9 live children at the same time
On May 4, 2021, a 25-year-old resident of Mali set a new world record for the number of living children born at the same time. Nine babies were born at one time. The former maximum dated 2009 - then the American gave birth to eight children. Read more here.
Abortions
Main article: Abortion
Maternal mortality
Main article: Maternal mortality
Documents
Main article: Electronic birth certificate
Newborns
Main article: Newborns
Notes
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