University of Texas researchers suggest that the female hormone estrogen makes women more vulnerable to ACL injury by weakening the ligament. Taking birth control pills lessens and stabilizes estrogen levels, reducing the likelihood of injury.

The study, from The University of Texas Medical Branch at Galveston, was published recently in Medicine & Science in Sports & Exercise, the official journal of the American College of Sports Medicine.

In the study, researchers examined a national insurance claims and prescription database of 23,428 young women between the ages of 15 and 19. They suggest from their findings that women with an ACL knee injury who were taking the birth control pills were less likely to need corrective surgery than women of the same age with ACL injuries who do not use them, according to a media release from The University of Texas Medical Branch at Galveston.

A possible suggestion from these findings, according to the research team, is that estrogen weakens the anterior cruciate ligament, making women more susceptible to injury.

The researchers also suggest, per the release, that women between the ages of 15 and 19 in need of ACL reconstructive surgery were 22% less likely to be using the birth control pill than non-injured women of the same age.

The study’s lead author and MD-PhD student Aaron Gray, states that puberty may offer an explanation for the rise in ACL injury cases in young women between ages 15 and 19. During puberty, he explains, there is a sharp rise in estrogen levels as well as growth spurts in the legs. Following one of these growth spurts, it takes time for the adolescent to develop good coordination.

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

[Source(s): The University of Texas Medical Branch at Galveston, EurekAlert]