Galveston, TX—New research has uncovered an unexpected advantage to using “the Pill”: It appears to reduce the risk of serious knee injuries in women who use the birth control method.

An article in the journal Medicine & Science in Sports & Exercise suggests that birth control pills reduce and help stabilize estrogen levels, leading to the lower rate of injury.

Background information in the article notes that female athletes are 1.5 to two times more likely than their male counterparts to injure their anterior cruciate ligament, ACL. Return-to-play rates after ACL injury are as low as 49% among soccer players, according to the report, which adds that the injury can lead to lifelong issues with knee instability, altered walking gait, and early-onset arthritis.

A University of Texas Medical Branch at Galveston–led research team used a national insurance claims and prescription database of 23,428 young women between 15 and 19 to determine that women with an ACL knee injury who were taking birth control pills were less likely to need corrective surgery than a control group of similar age and with similar injury who did not take birth control pills.

In light of a previous investigation finding that more ACL injuries in women occur when estrogen levels are highest during menstrual cycles, researchers sought to determine if estrogen makes women more vulnerable to ACL injury by weakening the ligament.

“Birth control pills help maintain lower and more consistent levels of estrogen, which may prevent periodic ACL weakness,” explained lead author Aaron Gray, an MD/PhD candidate. “With this in mind, we examined whether oral contraceptive use protected against ACL injuries that require surgery in women.”

Women between the ages of 15 to 19 have the highest rates of ACL injuries. Results indicate that those in need of ACL reconstructive surgery were 22% less likely to be using birth control pills than noninjured women of the same age.
Gray suggests that puberty could be responsible for the high number of ACL injury cases in teenagers because of the combination of a sharp rise in estrogen levels and growth spurts in the legs.

“Young athletes currently use birth control pills for various reasons including more predictable cycles and lighter periods,” Gray said. “Injury risk reduction could potentially be added to that list with further, prospective investigations.”

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