Oral contraceptives may lower the risk of anterior cruciate ligament (ACL) tears in women, according to a large observational study involving over 165,000 female patients (aged 15-49), published in The Physician and Sportsmedicine journal. The study, analyzing a decade of prescription and insurance information from a large national US database, find that oral contraceptives were most protective in young women aged 15-19 years.
The young athletic population
The findings have important implications for the nearly 1 in 2 athletes with ACL tears who are unable to return to athletic competition, and the 20–50% who develop arthritis within 10–20 years of their injury, researchers say. ACL injuries are extremely common, especially among the young athletic population, and are two to eight times more common in women than men. Previous research suggests that elevate estrogen may play a role in female athletes’ greater risk of ACL injury.
In this study, Dr. Steven DeFroda and colleagues from Brown University, Rhode Island, USA analyze the records of female patients (age 15-49 years) from the PearlDiver database; hence who were taking the most common types of oral contraception. Rates of ACL reconstruction in women taking oral contraceptives during the 12 months prior to injury; also undergoing surgery were compare to a control group of the same age with a similar injury who were not taking oral contraceptives.
A total of 465 women in the oral contraceptive group require surgical reconstruction of the ACL between 2007 and 2017 compare to 569 in the control group. Results show that women taking oral contraceptives were 18% less likely to require reconstructive surgery compare to match controls.
Pills containing the hormones
The authors speculate that taking pills containing the hormones estrogen and progesterone; hence may suppress the hormonal surges during the menstrual cycle, leading to a lower rate of injury. It’s likely that oral contraceptives help maintain lower and more consistent levels of estrogen and progesterone; which may lead to periodic increase in laxity and subsequent risk of tear (instead of Periodic acl weakness)”, says Dr. Steven DeFroda from Brown University, Rhode Island, USA who led the research.
Young athletes use oral contraceptives for a variety of reasons; so including regulating their menstrual cycle and/or preventing pregnancy. With careful assessment of the risks, injury risk reduction be another way; hence in which female athletes may benefit from their use,” says Dr. DeFroda.
This is an observational study, so no firm conclusions can be drawn about cause; also effect and the authors point to several limitations including that it only examine a limit number of risk factors; hence such as age and comorbidity, and did not assess participation in sports/activity level that might explain why some women tore their ACLs and others did not.
They also note that the study did not distinguish between athletic; so recreational, or accidental ACL injuries, and only look at women with injuries that are manage with surgery. A carefully control study that tracks athletes over time to see whether those who take oral contraceptives; which have fewer ACL injuries than others is need to confirm the findings.