Pregnant Belly Basics

Interesting facts to know as your baby bump grows.

Three Pregnant Women Sitting Halfpoint/Shutterstock

Inevitably someone will tell you (wrongly) that if you're carrying low you're having a boy, and vice versa. Here are some actual facts about baby bumps:

HIGHS AND LOWS: Carrying high or low does say something about your abs, according to John Thoppil, M.D., an assistant clinical professor of OB-GYN at Texas A&M University College of Medicine. "When a woman carries high, her abdominal muscles are often in good shape, while lax muscles from age, previous pregnancies or decreased fitness can cause her to carry low," he says. Thoppil adds that taller women usually have narrower pregnant bellies while shorter women carry wider.

SOONER OR LATER? Most bellies don't reveal a pregnancy until the second trimester. Until then, the uterus is usually hidden behind the pubic bone. "When women look like they are showing earlier, it is often due to the bloating that accompanies early pregnancy," Thoppil says. You may also show earlier if you have been pregnant before or your ab muscles are lax.

WHAT'S MY LINE? The linea negra—the vertical dark line that runs up your belly—is caused by pregnancy hormones. It is usually more pronounced in women with darker skin. "It will almost certainly fade after pregnancy," says Thoppil. (Your new "outie" bellybutton will likely go back to normal, as well.) As for stretch marks, they're mostly genetic; avoiding excess weight gain might help prevent them, he says, but nothing else is known to work.

TOO BIG OR TOO LITTLE: Starting at about 20 weeks, your doctor or midwife will measure your fundal weight, or distance from your pubic bone to the top of your uterus, at every prenatal visit. "It is a one-to-one correlation," Thoppil explains. "At 20 weeks, for instance, the measurement should be around 20 centimeters." If it deviates by 3 centimeters one way or the other, your care provider will most likely follow up with an ultrasound to see if the baby is too large or too small.

So it looks like the old adage, "Big belly means big baby," is just one of those enduring pregnancy myths. Click here as we sort through some more mom-to-be misconceptions with the help of two health experts.

Also, check out our Baby Your Bump page for tips on how to keep your pregnant belly as comfy as possible as it grows.