(Newser) – Childbirth can take a toll on a woman's body that rivals the damage endured by hardcore athletes—and a team of researchers has the MRI scans to prove it. The University of Michigan team found that 15% of women suffer pelvic injuries that don't heal, even when they faithfully follow the common advice of doing Kegel exercises after childbirth, say the researchers in a post. More specifically, 25% of women in the study suffered the equivalent of a sports stress fracture, 41% suffered muscle tears, and two-thirds suffered severe muscle strains, reports Vox. In the case of muscle tears, the muscle sometimes detached from the pubic bone, something no amount of Kegel exercises could fix. The injuries would have remained largely invisible if not for the MRIs.

"If an athlete sustained a similar injury in the field, she'd be in an MRI machine in an instant," says researcher Janis Miller. "We have this thing where we tell women, 'Well, you're six weeks postpartum and now we don't need to see you—you'll be fine.' But not all women feel fine after six weeks nor are ready to go back to work, and they aren't crazy." The team isn't advocating MRIs after all childbirths, notes the Guardian, in part because the women in the study were selected for high-risk factors. But Miller says women and doctors should guard against taking a "one-size-fits-all" approach to recovery and call in a specialist when pain lingers too long. (This is a scary time to get pregnant in Brazil, thanks to a virus.)

