Every time an athlete makes a sharp turn on the court, track or field, they put their ligaments to the test. Most athletes probably don’t spend much time thinking about their ACLs, until one day they feel a painful pop that signals months out of the game. But for one population of athletes who are most at-risk for this injury, birth control pills may represent the next wave of injury prevention.
Oral contraceptives, according to a paper published recently in The Physician and Sports Medicine, seem to have protective effects on the anterior cruciate ligaments (ACLs) of female athletes. According to data gleaned from 165,748 subjects, lead study author and orthopedic surgeon Dr. Stephen Defroda at Brown University found that female athletes between 15 and 19 years old who were on some form of oral contraceptive reduced their rate of ACL tears by 63 percent. Even athletes on contraceptives who did have ACL tears seemed to suffer less severe injuries: They were 18 percent less likely to require reconstructive surgery afterward.
“I think the most important takeaway from our paper is that younger females 15 to 19 were #1 most susceptible to tear, likely because this age group is the most active with regards to high risk activity such as athletics,” Defroda tells Inverse. “This age group was also the group that seemed to have the most potential benefit from oral contraceptive use.”
Devastating ACL injuries are common for many types of athletes. Across all sports, the American Academy of Pediatrics reported in 2017 that the ACL injury rate has been increasing by 2.3 percent per year for the past two decades. Analysis of NCAA injury statistics published in the Orthopaedic Journal of Sports Medicine showed that men’s football had the highest rate of ACL tears, followed by female gymnasts, and then female soccer players. Soccer, importantly, is an interesting case. Women’s soccer players experience far more ACL injuries than men’s soccer players, and these injuries, according to the NCAA, lead to “the longest time lost from any injury.”
Defroda adds that female athletes are more susceptible than male athletes in part because of “anatomy, biomechanics of gait, ligament size.” But he also adds that hormones, specifically estrogen, may play a role in their increased rates of injury.
“It is thought that hormone levels play a role, we just don’t know definitely what that role is yet, so long story short, the answer is that the jury is still out,” says Defroda. “
One potential explanation, he says, is that cyclical fluctuations in estrogen may actually affect how loose the ACL ligament is, opening it up to injury. That estrogen is where birth control pills come in. Hormonal birth control pills keep levels of hormones from fluctuating as much as they usually do. The idea is that less fluctuation may confer extra protection: “Oral contraceptive pills could potentially modify the risk of increased ACL laxity (which causes tear) by better regulating levels of estrogen,” says Defroda.
"This age group was also the group that seemed to have the most potential benefit from oral contraceptive use."
Although this theory has yet to be confirmed, Defroda’s study follows many others showing that there is some effect of birth control pills on ACL injury. Taken together, the case is building that there really may be enough of a protective effect from hormone regulators to actually lead regulatory agencies to recommend them to young female athletes. But whether that case is actually strong enough right now is the “million dollar question,” as Defroda puts it.
It’s not wild to think that contraceptives could be recommended for reasons outside of preventing pregnancy: For example, birth control pills are sometimes prescribed to combat acne or help manage particularly painful PMS.
But we still need to untangle whether certain formulations of birth control may be more beneficial for ACL health than others before any recommendations are made, says Defroda. And importantly, as with any medication, there are other risks that need to be considered.
“Our sports injury lab is currently doing some follow-up studies in conjunction with another group to really dig into these findings and see if certain oral contraceptive formulations, with regards to estrogen and progesterone dosing, are more protective than others,” he says. Eventually, they hope to determine “if this is something we should routinely recommend for this reason as well as for its primary use as a contraceptive.”
Right now, there are plenty of other reasons to take a contraceptive outside of sports. But in the future, the pill may prove its usefulness in combating a potentially season- or career-ending injury.
Methods: The PearlDiver database (www.pearldiverinc.com, Fort Wayne, IN) was queried for all OCP users amongst females aged 15–49. Female experiencing an ACL tear and undergoing surgery (CPT 29,888) were compared to a control group of females undergoing surgery for an ACL tear, but not on OCPs. Chi-squared testing was used to assess for significant differences in the rate of ACL reconstruction for the OCP and non-OCP users, according to age groups broken down into age intervals of 5 years.
Results: There were a total 82,874 patients in both the OCP and non-OCP groups. There was a total of 569 (0.69%) ACL reconstructions in the non-OCP group and 465 (0.56%) in the OCP group (p < 0.001). In the non-OCP group, patients aged 15–19 accounted for 29.35% of all ACL reconstructions, whereas, in the OCP group, this same age group only accounted for 13.33%. Among all age groups, the odds ratios for experiencing an ACL reconstruction while on OCP was 0.82 (χ2 = 0.001, 95% CI 0.72–0.92) compared to not using OCP. This protective effect was driven primarily by the 15–19 age group (odds ratio 0.37 (χ2 < 0.001, 95% CI 0.27–0.50). The number need to treat for OCP usage in the 15–19 age group was six patients.
Conclusions: OCPs have a protective effect on ACL tear, especially in the 15–19 age group, which exhibited a 63% reduction in the rate of tear. Consideration should be given to prescribing OCPs to younger athletes, after careful assessment of the risks of these commonly prescribed medications.