Fundal Height Measuring Large? Here's What It Actually Means

Like most people, pregnant women come in all shapes and sizes. That’s right, pregnant women are people, too, even though we aren’t always treated like a person based on random people’s comments on our bodies. For all the comments about how you’re showing, the most annoying one of all is, “Are you sure you’re not carrying twins?” when you know for a fact you aren’t. And why are you commenting on my body, Debra? If your fundal height is measuring large, and you know there's just one baby in there, what's actually happening?

Patricia A. Evans, a nurse practitioner and certified nurse midwife at MemorialCare Orange Coast Medical Center in Fountain Valley, California, tells Romper that most reasons are perfectly normal, including, “any fetal position other than cephalic (head down), incorrect dating, polyhydramnios (high amniotic fluid levels), or fibroids. Or perhaps multiple gestation (twins, triplets, etc.).” But usually it’s not, Debra. Thanks for asking.

You could also have weaker abdominal muscles from additional pregnancies, increasing your fundal height's size, Evans says. What to Expect also noted that most women tend to have bigger pregnant bellies in their second or third pregnancies because your abdominal muscles are looser from being stretched in your previous pregnancy, and you can definitely show sooner. Your belly has previously been stretched before, so it doesn’t take much for it to happen again. “Your body type might also be at play; some women carry their babies lower, which makes them appear to stick out more,” the website also noted.

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To measure your belly, your OB-GYN or midwife will perform a fundal height measurement each visit starting at about 12 weeks. This measures your baby’s growth and “involves measuring the distance from the top of the pelvic bone (symphysis pubis) to the top of the uterus (fundus),” according to Fit Pregnancy. “Measurements between 20 weeks and 36 weeks should be within two centimeters of the weeks of gestation," Elizabeth Stein, a midwife in New York City told Fit Pregnancy. "For example, at 32 weeks pregnant, the range of normal for fundal height is 30 to 34 centimeters. Any measurement larger or smaller should be a red flag that needs further evaluation."

If your belly is measuring too large based on the fundal height measurement, your OB-GYN will order an ultrasound to estimate the baby’s weight, Evans says. “But the majority of the time, your baby just may be on the bigger side but still healthy and normal.” The Fit Pregnancy article mentioned that the accuracy of fundal height measurements detecting potential problems range from 17 percent to 93 percent, with an average of 65 percent. That’s a bit all over the place, don’t you think? Stein said, “It's subjective at best and most accurate when done by the same person at every visit." But she added that “a woman's height, weight gain, and body fat should also be taken into account.”

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Just because you look like you’re four months pregnant in the first trimester — and continue to measure big throughout your pregnancy — doesn’t mean you’re fat, not eating healthy enough, or not getting enough exercise. Or that you’re carrying twins, Debra. If you’ve been pregnant before, your muscles are usually just stretched out from your previous pregnancy, or you could just be carrying low, have a lot of amniotic fluid, or your baby isn’t head down. If there's any actual concern, your OB-GYN will let you know.