How does the belly change during pregnancy?

A pregnancy lasts nine months. But in France, health professionals who follow pregnant women prefer to speak in weeks of amenorrhea (SA) or weeks of pregnancy (SG) to date a pregnancy and follow the main stages of fetal development. SA corresponds to the weeks during which the woman has not had her period. The first week of pregnancy begins on the day of conception (i.e. at the time of ovulation, approximately 14 days after the start of the last period if the cycle is 28 days). Thus, a normal pregnancy (excluding premature births) takes place in 41 WA (ie 39 SG). Note that the gestation period varies from one woman to another (baby can arrive earlier!).

When does the belly start to grow?

The baby bump appears on average at 4 months of pregnancy, but it varies from woman to woman and from pregnancy to pregnancy. In a woman who has already had a child, the second pregnancy will be visible sooner because the uterus has already been distended before. “The belly has a memory of sorts, the abdominal wall comes out faster after a first child”, Says Dr. Yannick Malard, obstetrician gynecologist. The morphology of the mother-to-be is also to be taken into account when taking a belly. In an overweight woman, the pregnancy belly will take longer to show than in a thin woman.
When the belly gets bigger, it means that the fetus is getting bigger too. “During the first 60 days of pregnancy, i.e. up to 9 SG and 11 WA, we speak of an embryo. The organs and morphology of the future baby are formed. From 11 weeks, the embryo becomes a fetus and it begins its period of growth with the maturation of the tissues and the functions of the organism.”, Explains the specialist. If a pregnant woman’s belly does not grow for 4 months, it is because the tiny embryo is being formed and takes up very little space in the uterus. The belly begins to grow as the fetus begins to grow and grow, that is, once all its organs are formed.

The three compulsory ultrasounds during pregnancy make it possible to verify these different stages of development of the future baby. The first ultrasound is performed between the 11th and 13th WA. It allows you to observe the embryo contained in the egg (or gestational sac), to listen to its heart, to measure the amount of amniotic fluid and to check that all the organs are formed. The second ultrasound is performed at around 22 weeks’ gestation (5 months pregnant). This makes it possible to observe the morphology of the fetus for a long time and to detect any anomaly. Finally the third ultrasound is done around 32 WA (end of the seventh month of pregnancy). This test allows you to check the baby’s good growth, the position of the placenta and that of the fetus, and the amount of amniotic fluid.

How much weight gain during pregnancy?

Like the onset of the baby bump, weight gain during pregnancy varies from woman to woman. “In theory, it is allowed to take between 9 and 12 kg. Beyond that, the risk of gestational diabetes increases”, Recalls the gynecologist. During the first three months of pregnancy, women are not expected to gain weight (or at least very little) because at the end of the 1st trimester, the unborn baby weighs less than 20 g and measures barely 5 cm. In some women, nausea during early pregnancy can even lead to slight weight loss.

According to the French National College of Gynecologists and Obstetricians (CNGOF), the usual weight gain during pregnancy breaks down as follows:

• 500 g per month in the 1st trimester.
• 1 kg per month in the 2nd trimester.
• 2 kg per month in the 3rd trimester.

“In the overall weight gain, you should know that the weight of the belly represents about 4 kg. At the end of pregnancy, the fetus weighs on average 3 kg, the amniotic fluid 500 g and the placenta 500 g. The rest of the total weight gain is therefore superfluous and can be dangerous during pregnancy but also difficult to lose after the baby is born. This is why gynecologists and midwives closely monitor the weight gain of their pregnant patients”, Explains Dr Malard.
Just because you’re pregnant doesn’t mean you have to eat for two! It is true that the recommended daily allowances increase a little during pregnancy, but the diet of pregnant women should, as far as possible, remain healthy and balanced. Women who gain too much weight during pregnancy tend to give in to their snacking cravings more readily than those who gain reasonable weight. But it must be said, it is more difficult to resist cravings for sugar during pregnancy because hormones, especially estrogen, cause cravings.

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When the baby “goes up” in the womb?

To check the evolution of the belly during pregnancy, we measure the uterine height, that is, the distance between the pubis and the uterine fundus. This measurement makes it possible to assess the size of the uterus during pregnancy but also to detect possible problems. It is part of the systematic clinical examination performed during pregnancy. Here are the values ​​(in cm) for a normal pregnancy:

• 4 months of pregnancy = 16 cm.
• 5 months of pregnancy = 20 cm.
• 6 months of pregnancy = 24 cm.
• 7 months of pregnancy = 28 cm.
• 8 months of pregnancy = 30 cm.
• 9 months of pregnancy = 32 cm.

“An excess of uterine height can be a sign of excess amniotic fluid and therefore of significant fetal growth, i.e. a large baby at the end of the pregnancy. Conversely, a uterine height lower than normal values ​​may be an indicator of growth retardation.”, Says Dr Malard.
The baby cannot be said to “rise” in the womb as the pregnancy progresses. Rather, it is the uterus which rises in the abdominal cavity when it no longer fits in the pelvic cavity because it is too large.

Don’t forget to take care of your body!

During pregnancy, the skin of the belly stretches quickly and this can cause stretch marks. That is why it is recommended to apply an anti-stretch mark treatment every day as soon as possible (from 4 months). Apply the treatment every day (twice a day from the 3rd trimester) on your stomach, your thighs and your buttocks by performing circular massages.

Venous disorders can also appear during pregnancy due to the increase in blood volume but also the compression of the inferior vena cava (it drains blood from the legs to the heart) by the uterus. If you have a feeling of heavy legs, do not hesitate to massage them regularly with an anti-heavy leg treatment based on natural ingredients with venotonic properties. Also talk to your doctor. He may prescribe compression stockings for you.

As you will have understood, the evolution of the belly during pregnancy depends on several factors. Every woman is different and every pregnancy is unique. Do not be worried if your belly “takes a long time” to grow or, on the contrary, “comes out” very early in the pregnancy.

Annabelle iglesias

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