Effect of Oral Contraceptives on Soft Tissue Injury Risk, Soft Tissue Laxity, and Muscle Strength: A Systematic Review of the Literature

BACKGROUND: Female patients are more likely than male patients to experience various musculoskeletal (MSK) injuries. Because MSK tissues are sensitive to the female hormones relaxin, estrogen, and progesterone, studies have examined whether hormonal contraceptives, which change female hormone levels, can alter the female MSK injury risk. These studies have reached contradictory conclusions, leaving unclear the influence of hormonal contraception on female MSK injury risk. HYPOTHESIS: Hormonal contraceptives act to decrease female soft tissue injury risk and soft tissue laxity. STUDY DESIGN: Systematic review; Level of evidence, 3. METHODS: Reviewers searched for clinically relevant studies evaluating the relationship between hormonal contraceptive use and soft tissue injuries, soft tissue laxity, muscle injuries, and muscle strength in the PubMed, Cochrane, Scopus, CINAHL, and Embase databases. Studies meeting inclusion criteria were scored by 2 independent researchers for risk of bias, imprecision, inconsistency, and indirectness with a template designed using the British Medical Journal Clinical Evidence GRADE (Grades of Recommendation Assessment, Development and Evaluation) scoring system and GRADEPro guidelines. Scores were uploaded into the GRADEPro scoring system software, which calculated each study’s final GRADE score (very low, low, moderate, or high quality). RESULTS: A total of 29 studies met inclusion criteria. Of the 7 studies evaluating oral contraceptive (OC) use and soft tissue injury risk, only 2 received a high quality-of-evidence score; all other studies received a very low score. The high-quality studies concluded that OC use decreases anterior cruciate ligament (ACL) injury risk. Only 1 of the 10 studies evaluating OC use and soft tissue laxity was found to have a high quality of evidence; this study determined that OC use decreases ACL laxity. CONCLUSION: Higher quality studies suggest that OCs decrease a female patient’s risk of ACL injuries and ACL laxity. The strength of these findings, however, is weak. Female patients are up to 8 times more likely to tear their ACLs than male patients. OCs may serve a therapeutic role in decreasing the sex disparity in ACL injury rates.