There is no one-size-fits-all answer to this question. Some women’s tummy muscles have been stretched by previous pregnancies so their bumps appear bigger, and some babies are larger than others.
A small bump might indicate weaker abdominal muscles or a shorter stature, but it can also be caused by benign growths in the uterus called fibroids.
Gestational Age
In the first trimester, your baby is developing rapidly. It’s important to get accurate measurements of your belly and fetus, such as fundal height, which helps your health care provider determine if the baby is growing properly. The measurement, which is taken at the same time each visit, should always be close to the date of your last menstrual period (LMP). Consistently measuring larger or smaller could indicate that something is wrong.
Your doctor or midwife uses your gestational age to track and monitor the fetus’s growth and development and to help you plan for your pregnancy. It’s also the reference point for the estimated due date (EDD).
A combination of history, clinical examination and early sonography are used to help estimate a woman’s gestational age in the first trimester. The first fetal ultrasound scan provides the most accurate estimation, as embryonic structures are visible on a standard sonogram.
By week 4 of pregnancy, the fetus is about the size of a poppy seed and cells begin to differentiate into specific organs. The heart, blood vessels and brain start to develop during this week. By week 7, the fetus has grown to about the size of a lentil, and its arms look like little paddles. By week 28, the fetus is about the same size as a cauliflower, and its eyes are opening for the first time.
Gestational Size
Every fetus develops at a different rate. That means that the average size for your baby by week may vary significantly.
Your obstetrician will use her experience, your fundal height (a measurement taken from your pubic bone), and an ultrasound scan to help determine your baby’s gestational age. She’ll also compare your baby’s size with other babies of the same gestational age to see whether your fetus is growing normally.
During the second trimester, you may notice that your bump is no longer nice and neat like a watermelon but instead is more lumpy and rounded. This is because the muscles and ligaments of your uterus are stretching to accommodate more space for your baby. If you’re expecting twins or triplets, your bump will grow differently to accommodate them.
A large bump isn’t necessarily a sign of a healthy pregnancy, though. It can indicate weaker abdominal muscles or a shorter stature, and it can also signal a noncancerous growth in your uterus called fibroids. These are muscular tumors that can grow during pregnancy and cause your tummy to look bigger than it should.
Your bump’s shape can also be impacted by the position your baby is in. A head-down position is ideal, and it’s usually assumed that your baby will assume this position by the end of the third trimester.
Weight Gain
Women often worry about how much weight they’re gaining and what it means for the health of their baby. A healthy amount of weight gain is around 28 to 40 pounds, depending on the woman’s pre-pregnancy weight and how high her bump is sitting by the end of the third trimester.
Some women’s bumps can look larger or smaller than their friends due to the shape of their bodies and how the bump is positioned. Regardless, this shouldn’t cause women to feel insecure about their own bumps.
The height of the bump can also be affected by other issues – such as having an underdeveloped core and weak abdominal muscles (a condition called diastasis recti) or having low levels of amniotic fluid. In these cases, the bump may be lower than usual and could suggest that a baby is growing too slowly or that a woman is at risk of bladder or kidney problems.
The height of the bump can also be influenced by whether it’s a first pregnancy or not, as the body tends to show more at the beginning. In addition, the height of the bump can depend on the mother’s genes as some women have stronger abdominal muscles than others. This can cause their bumps to sit higher, although not always. It’s worth talking to female family members about when they started showing as this can give a good idea of what to expect.
Abdominal Size
During pregnancy, your abdominal muscles can get stretched and flattened. This is called diastasis recti and is quite common. In some cases, your abdomen can look incredibly small and unnoticeable. This is because your uterus is growing upward and pushing down on your stomach, which makes it appear tiny. This is completely normal and can be caused by any number of things.
If you’re carrying your first child, your bump may be lower than that of someone who has carried a baby before because the abdominal muscles haven’t been stretched out as much. This is also true of women who are taller. It’s important to remember that bump size can change from week to week, especially closer to the end of a pregnancy. Babies often drop before labour, which can lower the bump even more.
Your doctor can check the thickness of your pregnant belly by measuring the fundal height. A measurement that’s higher than expected could indicate fetal macrosomia, or a fetus that’s larger than other fetuses of the same gestational age. This can be caused by conditions like diabetes.
There are many myths about how the size and shape of a baby bump can predict its sex, but these have never been proven to be accurate. If your doctor suspects that you’re carrying a boy or a girl, they’ll use non-invasive ultrasound scans to determine the sex.
