England and Arsenal midfielder Jordan Nobbs has called for more research into the links between anterior cruciate ligament injuries and menstrual cycles.
Nobbs, 26, was ruled out of this summer's Women's World Cup after damaging her knee in November.
She believes her period, which began the morning of the game with Everton, was "a very high factor" in the injury.
"Until I got injured I didn't really know that a lot of women do it while in their menstrual cycle," she said.
Research has suggested that ACL injuries - the most serious kind of knee damage - are more prevalent in female athletes than men.
One contributing factor is that oestrogen - a hormone released during menstruation - can increase joint flexibility, which could result in more damage if an athlete twists a knee.