The condition causes more than 70,000 maternal deaths

every year – but its causes continue to elude scientists.

After a glittering track and field career which saw her rack

up seven Olympic gold medals and 14 world championship golds, Allyson Felix assumed that pregnancy would be as smooth as her trademark running style.

“All my life, I’ve taken care of my body, my body has been my tool, and it has never really failed me,” says Felix. “I’ve trained and I’ve put demands on my body, and it’s always performed. [So] I was thinking [of having] like a beautiful natural birth, I’d gone to hypnobirthing, and all these things,” she says.

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But when Felix attended a routine check-up at 32 weeks, she was shocked to be told that she had severe pre-eclampsia, a pregnancy complication that causes dangerously high blood pressure levels and organ damage, and that she required immediate hospitalisation. The following day, doctors performed an emergency C-section, and her daughter Camryn was born two months early, subsequently spending the first month of her life in the neonatal intensive care unit.

Until then, there had been few signs that anything was amiss for Felix and her unborn baby, other than some swelling in her feet. “I wasn’t too alarmed by that, but I found out I was spilling protein and all these things about my blood pressure. It was terrifying. But our family got to go home,” she says.

While Camryn is now a healthy five year old, Felix is all too keenly aware of similar stories which have resulted in a far more tragic ending. In April 2023, her long-time team-mate Tori Bowie, a former world 100m champion and relay gold medallist at the Rio 2016 Olympics, died in childbirth from complications linked to pre-eclampsia. She was just 32.

“We were on numerous relay teams together, we competed against each other, with each other, and that was extremely shocking,” says Felix. “Someone that I’ve spent so much time with, it was really devastating.”