What exactly happens in a mother's body from pregnancy to birth?

It takes 280 days for humans to conceive a life.

From a tiny fertilized egg into a healthy embryo, and then from a chaotic primitive form into a mature fetus capable of surviving outside the mother's body - a long and grand history of life evolution takes place inside the tiny uterus.

The continuation of life has a complete set of biological codes. In a corner where no one notices, the horn of life blows vigorously, and thousands of sperm pass through the vagina, cervix, uterine cavity, and reach the fallopian tube. At this time, the number has been reduced from 100 to 300 million to 180, and the smartest and strongest one will break through the hard shell of the egg.

Experiments have observed that the moment the sperm enters the egg, the egg will burst into a strange light, and a new life officially begins.

In the noisy world, all this is happening quietly. People walk, eat, and sleep normally, but only mothers will be the first to notice the emergence of a new life, and then start a secret practice with this new life that belongs only to them...

Image source: Tuchong Creative

Early pregnancy

A new life that makes its presence felt

The entire human pregnancy period is divided into three stages: early pregnancy (1 to 12 weeks), mid-pregnancy (13 to 27 weeks), and late pregnancy (28 weeks to before delivery). The mother and baby have different performances in each stage.

During the first three months of pregnancy, calculated from the last menstrual period, the embryo is in a very unstable stage of development and is prone to various unexpected situations. This is why the older generation said that you cannot tell others about your pregnancy during the first three months.

During this stage, the fertilized egg will take root in the soft uterus and gradually differentiate into various organs and tissues. In the B-ultrasound of the 6th to 8th week, you can see the embryonic bud that looks like a "small seahorse" and the weak but powerful fetal heartbeat.

At this time, the rapidly differentiating embryos are more susceptible to damage from external 0 or 1, so we must strictly prevent teratogenic factors such as tobacco, alcohol, and radiation.

Three months later, the fertilized egg has become a small life that has taken human form, about the size of a loquat. The nuchal translucency scan (NT scan) around the 12th week is the first real meeting between the mother and the fetus.

At the same time, there are no obvious changes in the mother's belly, but the baby will use other signals to make you feel its presence strongly.

For example, they are often hungry, easily fatigued and sleepy, and their mood swings are drastic. Many people begin to suffer from morning sickness around the 6th week, and also have to face some minor embarrassments such as breast pain, frequent urination, increased secretions, and belly hair.

The root of these changes is hormones. In order to create a suitable and stable intrauterine environment for the embryo and maintain a normal pregnancy, hormones such as estrogen, progesterone, human chorionic gonadotropin (HCG), and prolactin change dramatically, quietly "reshaping" the mother's body and making it a more suitable "carrier" for nurturing the fetus.

For most mothers, the reaction in early pregnancy is not pleasant, but it is an inevitable part of pregnancy. Even the most delicate women have to face this unexpected change in their body and life.

Second trimester

Primary communication between mother and baby

Entering the second trimester, the mother becomes more comfortable and has a better appetite than in the early stages of pregnancy, while the growth and development of the fetus also accelerates accordingly.

In the second trimester, the uterus rapidly enlarges, the fundus of the uterus rises, and the living space of the internal organs is constantly compressed. Eventually, the fetus will expand its belly and grow outside the pelvis, commonly known as "showing pregnancy."

The growth of the fetus means that the mother's body is overloaded.

The heart works harder to pump enough blood, but it is still easy to feel anxious and short of breath; the intestines are squeezed and messed up, and constipation during pregnancy is a common operation; the bladder is pressed, urinating more frequently, and it becomes difficult to travel, and you have to find a toilet at any time; the pelvic cavity is squeezed, and pregnant women become people with "hemorrhoids"...

During this stage, in addition to routine prenatal checkups, the mother and fetus will also have to face several major tests, including major fetal anomaly screening, Down syndrome screening, and glucose tolerance screening. If the mother is a high-risk mother, she may also face the risks brought by amniocentesis. All of these test the mother's body and mind.

However, these discomforts seem insignificant compared to the specific changes in the fetus. The first time you hear the fetal heartbeat and the first time you hear the fetal movement, you can truly feel the existence of another life in your body, which is enough to withstand all the difficult times.

Listen to the baby's heartbeat with the help of a home Doppler fetal heart monitor. The "boom, boom, boom" sound is like the sound of horse hooves and trains. It is the regular and powerful beating of the little heart. Using "one body, two heartbeats" to describe the symbiotic companionship for ten months is not very scientific, but it is romantic enough.

From the 16th to the 22nd week, your baby can already hear your heartbeat, the voices of mom and dad, and begins to have primary communication with you - fetal movement.

At this time, the fetus is still weak and its body is as small as an avocado. It will greet you gently and playfully like a small fish. If you don't know what this feels like, you can put your palm on your cheek and gently push your cheek with your tongue. The touch of your palm is probably the feeling of early fetal movement.

Late pregnancy

The feeling of pressure from a "full-grade" fetus

If you can still go about your daily life as light as a swallow in the second trimester, you will find in the third trimester that even simple turning over and getting up have become extremely difficult.

The fetus grows at an astonishing rate in the third trimester, gaining 100 to 200 grams per week on average. Its tiny body gradually becomes fuller, and you can even tell the position of its feet and hands when it moves. The fetus' muscles are also stronger, and its organ systems are more complete, and it has gradually acquired the ability to survive outside the womb.

The mother will gain 500 grams or more per week, and the whole body will "expand" like a balloon. Edema, joint pain, pubic pain, lumbar pain, pelvic floor muscle relaxation and urinary incontinence will follow one after another, and stretch marks will also grow explosively. Even if you apply pregnancy oil in the early stage, it is very likely that it will not be able to resist the breakage of skin fibers, leaving irreversible lines.

When the time of delivery is approaching, the uterus of most pregnant women has already reached the chest. The uterus, which was once the size of an egg, has grown to be as heavy as a watermelon. The mother's body has reached its weight-bearing limit, and all internal organs have been squeezed to the limit. She may even have to rely on oxygen to maintain normal blood oxygen.

At this time, the uterus has rotated to the right, compressing the inferior vena cava and abdominal aorta, affecting the delivery of blood oxygen to the fetus. In order to prevent the fetus from suffocating, the mother will sleep in the left side position for a long time. In addition, the uterus compresses the bladder, causing frequent waking up at night, back pain when turning over, etc., which all reduce the sleep quality in the late pregnancy.

When the fetus enters the pelvis, the pressure from the uterine fundus will decrease, and the mother will suddenly feel that her breathing is easier and her appetite is better. At first, there will be occasional uterine contractions, and the secretion of relaxin will be strong, and the whole body will begin to prepare for childbirth.

In the third trimester, mothers are full of expectations for the new life, but they are also increasingly nervous and anxious. Fetal position, fetal movement patterns, amniotic fluid levels, umbilical cord conditions, fetal weight estimates, ultrasound indicators, any disturbance will affect the mother's tense nerves. Not to mention that they have to choose between a natural birth with "ten fingers open" and a cesarean section with "seven layers of abdominal rupture".

Compared to the mother's hardship, the fetus is having fun in the belly. Every day, he plays with his only toy, the umbilical cord, practices swallowing amniotic fluid, and burps to make himself fly. Some "funny" fetuses may even have the umbilical cord wrapped around the neck, the umbilical cord twisted, or the fetal position is abnormal, leaving the mother helpless.

The pregnancy process is long and arduous. Even with the support and care of the outside world, every woman who chooses to become a mother still has to bear the dual physical and psychological tests alone. The nurturing of life is short but beautiful. In 280 days, a human cell with no definite meaning becomes a high-level life form with hands, feet, thoughts and feelings. A fresh little life comes from oneself, which in itself is a kind of happiness.

The moment the fetus leaves the mother's body, you no longer purely own and protect him or her. All the checkup forms will be taken back by the hospital. You will no longer be able to hear the fetal heartbeat or feel the fetal movement. The lifelong separation of mother and child officially begins.

Pregnancy is a secret time that a mother and her child spend together. It will still be an important part of your life experience many years later. I hope you can spend these 280 days in peace and joy.

The article is produced by Science Popularization China-Starry Sky Project (Creation and Cultivation). Please indicate the source when reprinting.

Author: TUTU Mama Science Creator

Reviewer: Gao Hui Beijing Tiantan Hospital