You Probably Won’t Have an Oversize Baby

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Photo: ERproductions Ltd/Corbis

Nearly one in three babies born in the United States enters this world via cesarean section, and experts agree this figure is way too high. Now a recent study suggests that inaccurate baby-weight estimates could be partially to blame.

Some backstory: Trying to deliver a large baby vaginally can lead to complications like nerve damage if the shoulders get stuck. Doctors are advised to offer C-sections to patients when they believe the baby will be larger than 11 pounds. Per the American College of Obstetricians and Gynecologists, this is extremely rare. And according to a recent study published in Maternal and Child Health Journal, baby-weight estimates are often wrong, anyway.

Using a nationally representative survey of nearly 2,000 new moms, researchers found that four out of five women who were told their babies would be large had babies that were not, in fact, large. (Notably, they used the medical definition of a large baby, which is a newborn whose weight tops 8 pounds, 13 ounces, regardless of gestational age — not ACOG’s 11-pound figure. Only 8 percent of babies born in this country exceed the medical definition.)

Unfortunately, this knowledge does not exist in a vacuum. The mothers of suspected large babies — SLBs, per the study — were four-and-a-half times more likely to request a C-section than other moms. But it’s not always the patient: One woman told the New York Times that her doctor bullied her into having the procedure citing concern for her baby, who was predicted to be 11.5 pounds … and was born 7 pounds, 13 ounces.

Doctors really aren’t good at estimating birth weight right now, and ACOG guidelines released in 2014 state that ultrasound-based estimates of fetal weight aren’t very precise, especially when women are in their third trimester. They conclude that an SLB would only “rarely” be considered a reason to have a C-section.

You’re probably not going to have an 11-pound baby, so keep that in mind if you’re weighing the decision to have potentially unnecessary surgery.

You Probably Won’t Have an Oversize Baby