Mental, as well as physical challenges, face athlete-moms trying to return to their sport.

As Serena Williams’ frustration in the U.S. Open final boiled over, she smashed her tennis racket on the court at Arthur Ashe Stadium. It had become clear to her that, thanks in part to her play but mostly to a series of controversial penalties by chair umpire Carlos Ramos, she would not be claiming her 24th Grand Slam title.

To some observers, Williams’ behavior seemed egregious. But female athletes who are also mothers knew Williams’ distress was about more than this penalty, more than this match. It was about everything she had gone through to get here.

After giving birth in September 2017, Williams experienced post-delivery complications, including a pulmonary embolism and an abdominal hematoma. Returning home after a series of surgeries, she developed postpartum depression. Williams told Vogue magazine she was unable to get out of bed for six weeks.

While not all women experience the traumatic complications Williams did, it turns out that a shockingly high percentage of female athletes report struggles with postpartum depression. According to a study conducted by espnW,

32 percent of 37 athlete-moms reported experiencing symptoms of postpartum depression.

That’s far higher than the global average of 13 percent, according to the World Health Organization. So why would athlete-moms be more prone to postnatal mental health issues than other groups of women? And how can society support these women to help make their transition to new motherhood less difficult?

When we look at that 32 percent, we first have to think about the women who are self-reporting — professional female athletes — and what makes them unique. “They might be more honest than nonathlete moms, because athletes are so in touch with their bodies and how they’re feeling, and they know how to express that,” suggests ESPN’s Ramona Shelburne, a former softball player and expectant mother herself.

“When you’re an athlete, you get a lot of your strength from your physical strength,” says Shelburne. “Your identity is wrapped up in this idea that you can do anything.”

But after giving birth, an elite athlete can’t do anything — at least, not at the level she’s used to. In the six-week period following birth — called immediate postpartum — women are typically not encouraged to exercise, except for pelvic floor muscle strength training. But Dr. Kari Bø and her colleagues note in the 2016–17 evidence summary from the International Olympics Committee expert group meeting, published in the British Journal of Sports Medicine, that time period is “arbitrary.” “Anecdotally,” they write, “many elite athletes report starting exercise inside that period.”

So perhaps it’s time for the medical community to re-evaluate the guidelines given to elite athletes about resuming their exercise regimens — on a case-by-case basis, of course, and taking into account the differing recovery times for a vaginal birth versus a cesarean section.

Still, returning to elite shape takes time — long enough that athletes may miss multiple competitions, putting their world rankings or chance at winning a championship in jeopardy. While Bø and her colleagues note there aren’t sufficient studies about athletes returning to competition after birth, they suggest information can be gleaned from a similarly fit group: soldiers. According to Army Physical Fitness Test scores, the time it took for female soldiers to return to pre-pregnancy fitness was anywhere from two to 24 months, with a mean of 11 months.

To put that into perspective, Williams gave birth in September 2017. She returned to competition just three months later, at the Mubadala World Tennis Championship, ultimately falling to Jelena Ostapenko.

All this is to suggest elite athletes’ mental health following childbirth is inextricably linked to their physical recovery, which may explain the higher rates of postpartum depression they report. “I wanted it to happen overnight, so I dealt with a little depression there,” one elite female athlete told espnW in the anonymous motherhood survey.

“For professional athletes who are accustomed to structure, clear goals and a measurable bar of success, motherhood can be disorienting,” says Dr. Chantal Marie Gagnon, a psychotherapist and life coach who has researched maternal depression.

Gagnon also points out that few physicians and mental health professionals truly understand or know how to treat postpartum depression effectively. For instance, the misconception that postpartum depression is primarily caused by hormones is inaccurate. “In fact, postpartum depression peaks when the baby is 4 years old,” Gagnon says.

For athlete-moms, then, as with any new mother, proper medical care and evaluation tailored to their specific bodies and goals is crucial in navigating postpartum depression. It’s the foundation that will allow them to continue to compete at a high level post-birth.