New study finds birth control pills can lessen chance of knee injury in female athletes

A new study published in Medicine and Science in Sports and Exercise, the journal of the American College of Sports Medicine, found a link between birth control pills and often sports career-ending knee injuries.

The researchers at the University of Texas evaluated data on over 23,000 female athletes, aged between 15 and 19, who had incurred an ACL injury. They discovered that those on birth control pills had less serious injuries to the anterior cruciate ligament (ACL) and were 22 per cent less likely to require reconstructive knee surgery.

These findings follow on from a number of previous studies that have found a link between oestrogen levels and the chance of incurring knee injury, with females two to eight times more likely to injure their ACLs than their male peers. It’s long been known that the ACL contains hormone receptors and one school of thinking is that a surge in oestrogen levels, which typically happens during puberty or your monthly cycle, weakens the ligaments, therefore making a knee injury more likely.

Why women are more likely to incur an ACL injury

There are a number of reasons why women are at more risk of developing an ACL sprain or tear. The ACL is one of four ligaments that supports the knee joint but women’s ACL are proportionally smaller than men’s. As well as the ligaments, the knee is braced by the surrounding muscles and women have typically less muscular strength which leads to more potential for joint instability.

Furthermore, there are many anatomical differences between men and women, including the pelvis width that affects the angle that the leg bones connect; this is greater in women meaning more stress on the knee joint. Women also have a narrower notch where the ACL passes through the thigh bones. Biomechanical differences, in terms of landing, jumping and pivoting, can also play a role.

So, hormone levels may only be one factor in women being at more risk of an anterior cruciate ligament tear. Oestrogen medication, used as birth control, lowers levels of this hormone and also makes it consistent throughout the month, but the degree of protection afforded by taking the contraceptive pill has not been conclusively proven and it is important to realise that this is a prescription drug with known side effects.

If you think you may be suffering from an anterior cruciate ligament tear then call 08450 60 44 99 to book a consultation with knee specialist Mr Jonathan Webb. He offers consultations at the Nuffield Hospital in Bristol and the Fortius Clinic in London.