How Much Bigger Will My Belly Get Every Week in Pregnancy?

Watching your belly grow as your baby develops is one of the many joys of being pregnant. However, the state of your belly also can be a source of concern, particularly if your belly starts showing much faster than a pregnant friend’s belly or you aren’t showing at all into your fifth month. While you should bear in mind that everyone is different, knowing the basics of normal belly growth in pregnancy will help you assess your weekly progress.


You may feel consistently bloated in the early weeks of pregnancy, but chances are you won’t start showing until about your third or fourth month, according to pregnancy and parenting website BabyZone. Some of the factors that determine when you start showing are your size prior to pregnancy, your level of abdominal tone and whether you have had prior pregnancies. You are more likely to gain visible girth early on if you are thin and already have had a baby.

A Normal Range

Cropped pregnant woman measuring waist

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Your doctor will begin measuring your pregnant belly starting at about 20 weeks to assess your baby’s position, size and rate of growth, according to BabyCenter. To take this measurement – called the fundal height – the doctor will gauge the distance from your pubic bone up to the topmost part of your uterus. Although you may not get this measurement until you’ve reached the 20-week mark, your fundal height should start closely matching the duration of your pregnancy, centimeters to weeks, at about 12 weeks. For example, if you currently are 20 weeks pregnant, your fundal height should measure somewhere within a range of about 20 centimeters plus or minus 2 centimeters. Next week, your range should be about 19 to 23 centimeters.

Measuring Large

Various factors can lead your fundal height to measure more than 2 centimeters over what is expected for your pregnancy stage. Having looser abdominal muscles from a prior pregnancy, being overweight prior to pregnancy, having uterine fibroids, carrying multiples, having large amounts of amniotic fluid or having a baby that is positioned high could lead to a larger measurement, according to BabyCenter. You also may measure larger than normal if your due date isn’t accurate. If your belly size is large for your due date, your doctor may test you for gestational diabetes. Becoming diabetic during pregnancy can lead to a larger belly because it can make your baby larger than normal and lead to excess amniotic fluid.

Measuring Small

Cropped pregnant woman measuring waist

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You are measuring small if your fundal height is more than 2 centimeters smaller than what is expected. This can indicate that your due date is actually later than initially thought, you have very toned abdominal muscles or you have an abnormally small amount of amniotic fluid, according to BabyCenter. In some cases, having a smaller-than-normal measurement indicates that your baby isn’t growing as much as she should be growing. Your doctor will do further assessments to make sure your baby is as healthy as possible.