A paper was recently published that seemed to solidify the link between birth control and fewer ACL tears in women. Apparently, female athletes are twice as likely to tear their ACL compared to their male counterparts. However, when examining female athletes who took birth control versus those that did not take birth control–the birth control group were less likely to need corrective surgery. The study used this paradigm to study over 20,000 women.
So what exactly may be going on? The running theory is that somehow estrogen makes females more susceptible to ACL injuries by weakening the ligament. So by using birth control, lowering estrogen and maintaining a consistent level may be reducing the risk of tearing the ACL. A piece of evidence that supports this idea is the fact that women seem to be susceptible to ACL injury during their menstrual cycle when estrogen levels are high.
A word of caution though–this study did NOT establish causation. In fact, the only conclusion we can reliably make based on this study is (and I quote): “The girls with the highest rates of ACL surgery were 22 percent less likely to be taking birth control pills than those who didn’t have an ACL injury.” So while there seems to be a link between birth control and fewer ACL tears, this is not equivalent to taking birth control actually reducing ACL injury. More studies are needed to truly elucidate this phenomenon. At the very least, I think it’s an interesting study that may have implications for serious athletes!