Teen girls on the pill have fewer knee injuries

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WEDNESDAY, March 23, 2016 (HealthDay News) -- Teen girls who take birth control pills may be less likely to seriously injure their knees than those who don't take the pill, a new study suggests.

"Young athletes currently use birth control pills for various reasons, including more predictable cycles and lighter periods," said study author Aaron Gray, an M.D./Ph.D. student at the University of Texas Medical Branch at Galveston.

"Injury risk reduction could potentially be added to that list," he said, if future studies confirm what the new study found.

The study did not prove a cause-and-effect relationship between birth control pills and knee injuries. The researchers only found an association between these factors.

Female athletes are up to twice as likely to suffer an anterior cruciate ligament (ACL) injury as male athletes, the study authors said. The ACL connects the top and bottom parts of the knee.

Researchers reviewed data from more than 23,000 girls between the ages of 15 and 19 in the United States.

The teens with ACL injuries who were on the birth control pill were less likely to need corrective surgery than girls not taking the pill who had ACL injuries.

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.

Experts have theorized that the female hormone estrogen may make women more vulnerable to ACL injuries. Estrogen may weaken the ligament, the study authors said. They noted that a previous study found that women have a greater risk of ACL injuries during their menstrual cycle when estrogen levels are high.

"Birth control pills help maintain lower and more consistent levels of estrogen, which may prevent periodic ACL weakness," Gray said in a university news release.

The study was published recently in the journal Medicine & Science in Sports & Exercise.

SOURCE: University of Texas Medical Branch at Galveston, news release, March 18, 2016

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