Like many women who learn they must undergo a last-minute c-section, Chontel Duncan was nervous and upset when she got the news: "I CRIED I felt like I failed," the fitness trainer wrote in a moving post on Instagram about her scar, which she now wears as a badge of pride.

But during her surgery, Duncan, 27, experienced another complication that's quite rare: Her abdominal muscles made it challenging for doctors to deliver her son, she said. 

"They struggled to rip Jeremiah from my tummy as my abs locked him in super tight as I began vomiting during the operation," Duncan wrote. "This is why my scar was cut up on my right side because the surgeon had to cut me further [and] use forceps to successfully get Jeremiah out."

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"Perhaps a down side to a strong core," Duncan added.

Well-defined abs can be more difficult to separate during a c-section, says Joshua Klein, MD, an assistant professor of Obstetrics, Gynecology, and Reproductive Science at the Icahn School of Medicine at Mount Sinai. "Especially in a thin/petite patient, creating enough space to get to the baby, and then get it out is the main challenge of the procedure, and tight abdominals can make the tight space effectively even tighter," he explained in an email to Health.

But Jennifer Gunter, MD, an ob-gyn based in San Francisco, doesn't think having strong abs is something pregnant women need to worry about. The epidural administered before a c-section relaxes those muscles so they don't interfere with surgery, she wrote to Health. (Neither Dr. Klein nor Dr. Gunter have treated Duncan.)

"Sometimes young, healthy people have a tight fascia, the layer [of tissue] beneath the muscles, and that might have been what [Duncan's] OB meant," suggested Dr. Gunter. "It doesn't mean stop working out," she added, since having a tight fascia is not related to core work.

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A toned core can actually be a great help during childbirth, points out Dr. Klein, who is also the chief clinical officer at Extend Fertility in New York City. It can "increase the power of the mom's 'pushes' and can potentially increase the chance of a successful vaginal delivery," he added. 

To learn more about what exercises are considered safe for moms-to-be (planks are a-ok!), check out our guide to the best (and worst) workouts for pregnant women.