Pregnant Belly: First, Second, and Third Trimesters (2023)

Watching your pregnant belly grow and change can be fascinating. However, many questions and concerns can also accompany the changes in your abdomen during pregnancy.

Some pregnant bellies may look like basketballs, others like watermelons, and others may not show at all. Some are carried high, and others low or even wide. Your pregnant belly is unique and will change throughout your pregnancy depending on factors like your height, weight, pre-existing conditions, muscle mass, trimester, baby’s size, and more.

There is no one “normal” pregnant belly shape, size, or appearance. Still, there are some general things to know about how your pregnant belly will develop throughout your pregnancy.


An average full-term pregnancy is 40 weeks, but this can vary. Your pregnant belly will change significantly over that time period. While every person is different and there is no universal chart to monitor pregnant belly shape or size, it can be helpful to use pregnancy trimesters to gauge changes in your pregnant belly.

Each pregnancy is divided into trimesters, in which your body experiences unique physiological, hormonal, and physical changes as your baby grows.

Trimesters are defined as:

  • First trimester: First day of your last menstrual period to the end of the 13th week
  • Second trimester: 14 weeks to the end of the 27th week
  • Third trimester: 28 weeks to end of pregnancy

First Trimester

You may not know you’re pregnant until four weeks or more through your first trimester, so you may not notice any changes in your pregnant belly during this time.

The “baby bump” typically develops in the second trimester of pregnancy, so don’t worry if you aren’t seeing any of the tell-tale pregnant belly signs during your first trimester.

Some people may notice a small bump one day and a normal belly the next. Don’t let this concern you. Due to hormonal fluctuations in your first trimester, you may experience bloating, gas, or constipation that can all create the illusion of a bump.

While your belly may not change much during the first trimester, you may notice other bodily changes in your skin and breasts.

Average weight gain during the first trimester is 1 to 4 1/2 pounds.

Second Trimester

Your pregnant belly will begin to “show” at the end of your first trimester and the beginning of your second trimester. For most people, this happens around weeks 12 to 16, but everyone is unique.

Certain factors may impact whether your pregnant belly shows earlier or later. Those who have had a previous pregnancy tend to develop a noticeable pregnant belly earlier, due to looser muscles and ligaments. Lower body weight and shorter stature also may lead to showing earlier. People who are taller or have more developed abdominal muscles may show later.

At the beginning, your bump will only be noticeable when you aren’t wearing clothes, so you and your partner will be the first ones to notice it. Around week 20, it will be visible through your clothes to others, too.

Around this same time, usually weeks 16-20, you may start wearing maternity clothes to accommodate your pregnant belly.

You will also notice some new skin changes on your pregnant belly during your second trimester. Some people develop stretch marks, and others may develop a dark vertical line. This is all normal and will differ person by person. If you do have concerns, consult with your healthcare provider.

Average weight gain during the second trimester is 1 to 2 pounds each week.

What Is Fundal Height?

Third Trimester

Most people will have an apparent pregnant belly throughout their third trimester, but the size and shape can be very different for each person.

Some people carry “high,” and others carry “low,” which can depend on your stature, muscle composition, as well as the baby’s position. You may also notice your pregnant belly drop lower, sometimes overnight, when you’re close to the end of your pregnancy.

Carrying “wide” may be due to your baby being positioned in a side-lying position, or your belly may appear wide due to short height or smaller abdomen.

Old wives’ tales say that a “high” belly indicates a girl baby and a “low” belly indicates a boy baby. This is just a myth. In reality, your pregnant belly position has nothing to do with the baby’s sex. It will be influenced by other factors such as your weight, height, previous pregnancies, and pre-existing conditions.

As you progress through your third trimester, you and your partner may also now visibly notice your baby’s kicks, shifts, and movements through your pregnant belly.

Your belly will also feel at its heaviest during the third trimester. Up to 78% of pregnant people may experience ongoing round ligament pain or other pelvic pain. If this happens to you, talk to your healthcare provider. They may recommend multiple solutions, such as a belly band for support.

Average weight gain during the third trimester remains steady at 1 to 2 pounds per week.

Common Concerns

You may wonder whether your pregnant belly “should” have shown yet, whether your belly button changes are normal, if your weight gain is typical or atypical, and more. Know that everyone is unique and there is no single set of rules or expectations for how your pregnant belly should or should not appear.

What is most important is that your developing baby remains healthy, and your obstetrician-gynecologist (OB-GYN) will help you monitor this. Below are some common concerns, but it’s always a good idea to consult with your OB-GYN if you have worries throughout your pregnancy.

Belly Button

You may notice changes in your belly button throughout pregnancy. These changes will likely not be painful, but they may still concern you.

In some people, a belly button that was formerly an “innie” may “pop out.” There is not much research on this phenomenon, but it is a common anecdotal change. This occurs when the uterus enlarges and places pressure on the abdominal wall. It is most likely to occur in week 26 or later, in your third trimester.

If your belly button becomes painful during pregnancy, consult with your healthcare provider to rule out an umbilical hernia.

Stretch Marks

Stretch marks, also called striae gravidarum, are common and natural occurrences throughout pregnancy that affect up to 90% of people. However, the possibility of stretch marks may be concerning to some people.

Stretch marks result from connective tissue changes as your body’s size rapidly changes throughout pregnancy. These occur most commonly along your belly, as well as your breasts, thighs, and other areas.

Risk factors for developing stretch marks include:

  • Younger age
  • Family history of stretch marks
  • Increased pre-pregnancy weight
  • Increased pre-delivery weight
  • Increased baby size or birth weight

Know that stretch marks are a completely normal part of pregnancy due to the immense changes your body is going through to help grow and support your baby. If you want to prevent stretch marks, research indicates that Centella asiaticaextract, hyaluronic acid, and daily massages may help, but consult with your healthcare provider first.

Keeping your belly moisturized throughout pregnancy can also help treat stretch marks if they develop. A randomized placebo-controlled trial among pregnant people found that moisturizers that contain rosehip oil, vitamin E, hydroxyprolisilane C, and Centella asiaticatriterpenes were most effective at reducing the severity of stretch marks.

Weight Gain

Everyone will gain weight throughout pregnancy, but the exact amount will differ from person to person based on factors such as your pre-pregnancy body mass index (BMI).

BMI is an imperfect way of conceptualizing someone’s body fat composition, but it is what the Centers for Disease Control and Prevention (CDC) currently uses to guide expected pregnancy weight gain.

According to the CDC, expected weight gain from a pregnancy of one baby is:

  • BMI < 18.5 (underweight): 28-40 pounds
  • BMI 18.5-24.9 (normal weight): 25-35 pounds
  • BMI 25.0-29.9 (overweight): 15-25 pounds
  • BMI > 30.0 (obese): 11-20 pounds

Your baby itself will weigh about 7 to 8 pounds by the end of your pregnancy. Among other contributions to your baby bump are increased size and weight of your uterus, plus amniotic fluid and the placenta.

You may also notice that you are gaining weight but your pregnant belly is not getting bigger. Don’t let this worry you. Although you gain weight throughout pregnancy, this is distributed to areas of your body other than your belly.

These areas include:

  • Breasts: 1 to 3 pounds
  • Placenta: 1 1/2 pounds
  • Amniotic fluid: 2 pounds
  • Increased retained fluid volume: 2 to 3 pounds
  • Increased blood volume: 3 to 4 pounds
  • Increased fat stores: 6 to 8 pounds

B Belly vs. D Belly

Not all pregnant bellies look the same, and this is true for the silhouette of the bump as well. Those with a “D”-shaped belly may be told they look like they’re carrying a basketball. The outline of the belly is smooth and round, like the letter “D.”

Other people may have a “B”-shaped belly, where the belly consists of two bumps stacked on top of each other, below the breasts. Those who have a higher pre-pregnancy weight are more likely to have a “B”-shaped belly. The baby’s position, if they have their head and feet facing outward, may also contribute to a “B” shape.

Dark Line

Some people may be concerned about a dark line that develops along the belly during pregnancy. This dark line is called the linea nigra, and it is completely normal.

The linea nigra is a vertical line about 1 centimeter (0.4 inches) wide. It typically runs from the belly button down to the pubis. It can appear in the first trimester as an early sign of pregnancy, and then it thickens and darkens through pregnancy.

Researchers theorize that the linea nigra is caused by hormonal changes during pregnancy. In almost all cases, it lightens and disappears after birth.

Body Image

It is very valid to feel your growing pregnant belly affect your body image and mental health throughout pregnancy.

Women, in particular, have a socially constructed ideal of thinness. For some people, a pregnant belly is seen not as a happy sign of their developing baby but as an obstacle to good body image.

Qualitative research on first-time pregnancy found that some people become dissatisfied with their bodies early in pregnancy and feel that their bodies are “alien.” Another qualitative study found that factors that promoted positive body image during pregnancy included:

  • Focusing on the functionality of your pregnant belly and body
  • Partner support, including positive feedback about the pregnant body
  • Open conversations about weight and body image in antenatal health care

A Word From Verywell

For some people, pregnancy is a joyful time, and for others, it is a time of emotional upheaval and stress. For many, it is an emotional roller coaster of both.

Because your belly is the most apparent manifestation of your pregnancy, it’s easy to focus your questions, concerns, and stress on the appearance of your belly.

It’s important to know that no pregnant belly is the same. However, understanding the trimesters and the explanations behind common concerns, such as belly button changes or stretch marks, can help alleviate your worries.

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