How the Belly Grows During Pregnancy: Trimester by Trimester

The way the belly grows during pregnancy is related to the maternal anatomy and the size of the uterine cavity. Learn more!
How the Belly Grows During Pregnancy: Trimester by Trimester

Last update: 11 April, 2022

A sign that characterizes every pregnant woman is her enlarged belly. The evolution of its size will depend on the volume of the uterus, which is closely related to the growth of the baby and the maternal anatomy. In the following article, we’ll tell you how the belly grows during pregnancy trimester by trimester and other highlights of this topic.

How the belly grows during the first trimester of pregnancy

The way in which the belly grows during pregnancy is very variable among women and it’s complex to determine standard measures of said evolution. This is because there are multiple factors that directly or indirectly affect its size.

Among them, the maternal body structure, the size of her pelvis, the number of previous pregnancies, the amount of amniotic fluid, the size of the placenta, and the position and volume of the baby.

Even so, in general terms, we can say that the belly doesn’t undergo major changes during the first month, as the uterus practically doesn’t expand.

During the second month of pregnancy, many pregnant women may experience a slight inflammation of the belly, due to the fact that the uterus begins to thicken its walls and the placenta begins to expand. From this point on, it’s normal for clothing to feel tighter in the waist area.

By the third month of gestation, it’s already possible to palpate the upper pole of the uterus above the pubis. The baby weighs about 40 grams and the amount of amniotic fluid is quite considerable. These changes cause the womb to become more rounded and begin to push against the walls of the maternal abdomen, especially if the woman has had previous pregnancies.

A pregnant belly at three months.
Towards the end of the first trimester, it’s possible to glimpse the growth of the belly, especially when it’s not your first pregnancy.

How the belly grows during the second trimester of pregnancy

From the second trimester on, the belly begins to grow in giant steps. Between weeks 12 and 16, moms begin to notice that their abdomen has become distended and that, little by little, it takes on the typical shape of pregnancy. In fact, many women must begin to adapt their wardrobes for this new stage.

During the fourth month, the bottom of the uterus (or upper end) is about 2 inches below the navel, and by this time, the baby weighs about 5 ounces and measures about 5 inches.

One aspect that determines the size of the belly at this time is the number of previous gestations. This is because when a pregnancy has already been experienced, the abdominal muscles are more flexible and this leads them to give in easily to uterine growth.

By the end of the sixth month, the uterine fundus is about 2 inches above the navel and the belly is the size of a soccer ball. In this instance, you can already see how the skin of the abdomen responds to this great anatomical change. Therefore, it’s normal for the epidermis to feel quite tense and itchy at night.

Although the belly grows considerably during this period, its size doesn’t usually cause discomfort yet, nor does it prevent the performance of daily activities. This is why the second trimester stands out as being the most bearable of the entire pregnancy.

A pregnant woman sitting by the ocean stretching.
Although during the second trimester the belly grows a lot, its size still doesn’t cause discomfort or prevent daily activities.

The third trimester of pregnancy: A growth spurt

The third trimester of pregnancy is characterized by the accelerated development of the baby, which determines the size of the belly.

It’s normal to notice an exponential growth of the belly, as well as a heaviness that arouses discomfort, such as pain in the lower back.

In the eighth month, the upper end of the uterus is situated below the ribs and exerts pressure on the organs of the chest cavity.

This prevents the full expansion of the lungs, which causes the mother to tire quickly, breathe faster, and sometimes also have trouble sleeping. Other common symptoms of this stage are heartburn, slow digestion, and frequent urination.

During the days before birth, the baby takes its starting position and fits into the pelvis. This, together with the weight of the belly itself, causes a sudden drop in it, which is a sign of the imminent arrival of the baby.

After delivery, the belly slowly returns to its normal size. But this doesn’t happen overnight. Rather, it takes about 6 weeks, if not more.

Accompany the growth of your belly in the best possible way

It’s important to eat a balanced diet during pregnancy, hydrate yourself properly, and use moisturizing creams or lotions on your belly to avoid stretch marks.

If you have doubts about the changes that may appear in your abdomen and the care it requires, you should talk them over with your doctor and midwife.

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