Menstrual dysfunction rate and delayed menarche in top athletes of team games

The Prevalence of Menstrual Cycle Disorders and Menstrual Cycle-Related Symptoms in Female Athletes: A Systematic Literature Review

BACKGROUND

Menstrual cycle (MC) disorders and MC-related symptoms can have debilitating effects on the health and performance of female athletes. As the participation of women in sports continues to increase, understanding the prevalence of a range of MC disorders and MC-related symptoms may guide preventive strategies to protect the health and optimise the performance of female athletes.

OBJECTIVE

To examine the prevalence of MC disorders and MC-related symptoms among female athletes who are not using hormonal contraceptives and evaluate the assessment methods used to identify MC disorders and MC-related symptoms.

METHODS

This systematic review was performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). Six databases were searched until September 2022 for all original research that reported the prevalence of MC disorders and/or MC-related symptoms in athletes not using hormonal contraceptives, which included the definitions of the MC disorders examined, and the assessment methods used. MC disorders included amenorrhoea, anovulation, dysmenorrhoea, heavy menstrual bleeding (HMB), luteal phase deficiency (LPD), oligomenorrhoea, premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD). MC-related symptoms included any affective and physical symptoms related to the MC that do not cause significant personal, interpersonal or functional impairment. The prevalence data across eligible studies were combined, and all studies were qualitatively synthesised to evaluate the assessment methods and tools used to identify MC disorders and MC-related symptoms. The methodological quality of studies was assessed using a modified Downs and Black checklist.

RESULTS

Sixty studies involving 6380 athletes were included. A wide range of prevalence was observed for all types of MC disorders, with a dearth of data on anovulation and LPD. Based on pooled data, dysmenorrhoea (32.3%; range 7.8-85.6%) was the most prevalent MC disorder. Studies reporting MC-related symptoms mostly examined the premenstrual and menstruation phases, where affective symptoms appeared more prevalent than physical symptoms. A larger proportion of athletes reported symptoms during the initial days of menstruation compared with the premenstrual phase. MC disorders and MC-related symptoms were retrospectively assessed using self-report methods in 90.0% of studies. Most studies (76.7%) in this review were graded as moderate quality.

DISCUSSION

MC disorders and MC-related symptoms are commonplace among female athletes, warranting further research examining their impact on performance and preventive/management strategies to optimise athlete health. To increase the quality of future studies, researchers should adopt standardised definitions of MC disorders and assessment methods such as a combination of calendar counting, urinary ovulation tests and a mid-luteal phase serum progesterone measurement when assessing menstrual function. Similarly, standardised diagnostic criteria should be used when examining MC disorders such as HMB, PMS and PMDD. Practically, implementing prospective cycle monitoring that includes ovulation testing, mid-luteal blood sampling (where feasible) and symptom logging throughout the MC could support athletes and practitioners to promptly identify and manage MC disorders and/or MC-related symptoms.

TRIAL REGISTRATION

This review has been registered in the PROSPERO database (CRD42021268757).

Exercise-related female reproductive dysfunction

Clinical or biochemical abnormalities of gonadal function, consisting of delayed puberty, luteal phase deficiency, oligo-amenorrhea or anovulation, occur in girls and women participating in strenuous sports. The evidence of a causal relationship between athletic activity and menstrual dysfunction has led to increased interest, also because the number of women who practice sports has increased rapidly. The pathogenesis of exercise-related female reproductive dysfunction (ERFRD) is not completely clarified. The heterogeneity of sports practice, the role of overtraining and other factors, as adequate calorie balance or the assumption of exogenous steroids, could play a primary role in the comprehension of the pathogenic mechanisms of reproductive dysfunction. The interest of physicians about ERFRD is also due to the consequences of reduced gonadal function on women's health. Apart from some short-term transient effects (i.e. on muscle, genito-urinary tract or behavior), hypoestrogenemia can induce long-term deleterious effects, as premature osteoporosis and lifelong impairment of skeletal structure. In view of the possible short-term (infertility) and long-term (osteoporosis) consequences of ERFRD, correct physical training and adequate diet approach are mandatory to prevent or to revert neuroendocrine abnormalities so frequently reported in girls and women participating in recreational or competitive athletic activities.

Effect of altered reproductive function and lowered testosterone levels on bone density in male endurance athletes

It is apparent that bone density in male athletes can be reduced without a concomitant decrease in testosterone, suggesting that bone density and testosterone concentrations in the normal range are not closely related in male athletes. Further research is necessary to monitor concurrent changes in bone density and testosterone over a period of time in exercising males. In any case, the effect of exercise on the male reproductive system does not appear as extreme as that which can occur in female athletes, and any impact on bone density is not nearly as evident. These results imply that factors apart from testosterone concentrations must be responsible for the observed osteopenia in some male athletes. Many factors have the potential to adversely affect bone density, independently of alterations in reproductive function. These include low calcium intake, energy deficit, weight loss, psychological stress, and low body fat, all of which may be associated with intense endurance training. Future research investigating skeletal health in male athletes should include a thorough assessment of reproductive function in addition to these other factors.