Reviewed by Tyler Tice, PT, DPT, OCS, ATC
This scoping review published in Sports Medicine (2024) synthesized literature from 1986–2023, including both published and unpublished studies, to examine the influence of menstrual cycle phases (MCP), menstrual irregularities (MI), and hormonal contraceptive (HC) use on musculoskeletal (MSK) injuries among female athletes aged 13–45 years. The study designs included are as follows: cross-sectional (43), cohort (21), case-control (12), case series (11), case studies (7), and randomized controlled trials (1)
Most studies investigated menstrual irregularities and menstrual cycle phases as injury risk factors. Additionally, most of the research focused on elite or professional-level athletes. Pregnant, perimenopausal, and menopausal women were excluded.
Hormonal Influence on Injury Risk
Injury rates in comparable sports are generally higher among female athletes. Continuous hormonal fluctuations are hypothesized to influence the structure and mechanical properties of muscle, tendon, bone, and ligaments. Both menstrual function and hormonal contraceptive use alter endogenous reproductive hormone levels, potentially affecting injury risk. A typical menstrual cycle includes the follicular phase, ovulation, and the luteal phase respectively. Hormonal fluctuations throughout these phases have been associated with increased risk of both acute and overuse injuries.
In female soccer players, injury incidence appears greatest during the late follicular phase. Increased risk of muscle, tendon, and anterior cruciate ligament (ACL) injuries has also been observed during this phase. Additionally, peak estrogen levels during ovulation are associated with increased ligament laxity, altered strength, and reduced neuromuscular control, which may predispose athletes to injury. However, findings across studies are inconsistent, and a direct causal relationship between menstrual cycle phase and injury has not been definitively established.
Menstrual Irregularities and Injury
Menstrual irregularities are prevalent among female athletes and are associated with elevated injury risk. High school athletes with menstrual dysfunction demonstrate greater time-loss severity compared to athletes with regular menstrual cycles.
The Female Athlete Triad, now referred to as Relative Energy Deficiency in Sport (RED-S), highlights the interrelationship between low energy availability, menstrual dysfunction, and reduced bone mineral density. RED-S also has implications for cardiovascular health, immunity, metabolic rate, and overall menstrual function. Athletes with menstrual irregularities are particularly susceptible to bone stress injuries due to reduced estrogen levels and compromised bone health.
Hormonal Contraceptives and Injury Risk
Approximately half of female athletes use hormonal contraceptives, including: oral contraceptive pills (OCPs), intrauterine devices (IUDs), injections, transdermal patches, implants, and vaginal rings. Hormonal contraceptives suppress endogenous hormone production and eliminate typical cyclical fluctuations. Some literature included in this review suggests that hormonal contraceptives, particularly oral contraceptives, may provide a protective effect against injury. Among female athletes, some studies suggest that oral contraceptive use, with or without neuromuscular training, may improve dynamic knee stability and potentially reduce ACL injury risk. However, evidence from the general population indicates that combined hormonal contraceptives are not protective against MSK injuries.
Overall, evidence remains inconclusive due to methodological variability across studies. Despite inconsistencies in the literature, physical therapists should not dismiss menstrual and hormonal influences, as they may represent an important piece of the multifactorial puzzle in injury risk and rehabilitation for female athletes.
Reference:
MacMillan, C., Olivier, B., Viljoen, C. et al. The Association Between Menstrual Cycle Phase, Menstrual Irregularities, Contraceptive Use and Musculoskeletal Injury Among Female Athletes: A Scoping Review. Sports Med 54, 2515–2530 (2024). https://doi.org/10.1007/s40279-024-02074-5