Objective: To examine the prevalence of menstrual dysfunction in the total population of Norwegian elite female athletes and national representative controls in the same age group.

Methods: A detailed questionnaire that included questions on training and/or physical activity patterns, menstrual, dietary, and weight history, oral contraceptive use, and eating disorder inventory subtests was administered to all elite female athletes representing the country at the junior or senior level (aged 13-39 years, n = 938) and national representative controls in the same age group (n = 900). After exclusion, a total of 669 athletes (88.3%) and 607 controls (70.2%) completed the questionnaire satisfactorily.

Results: Age at menarche was significantly (p<0.001) later in athletes (13.4 (1.4) years) than in controls (13.0 (1.3) years), and differed among sport groups. A higher percentage of athletes (7.3%) than controls (2.0%) reported a history of primary amenorrhoea (p<0.001). A similar percentage of athletes (16.5%) and controls (15.2%) reported present menstrual dysfunction, but a higher percentage of athletes competing in leanness sports reported present menstrual dysfunction (24.8%) than athletes competing in non-leanness sports (13.1%) (p<0.01) and controls (p<0.05).

Conclusions: These novel data include virtually all eligible elite athletes, and thus substantially extend previous studies. Age at menarche occurred later and the prevalence of primary amenorrhoea was higher in elite athletes than in controls. A higher percentage of athletes competing in sports that emphasise thinness and/or a specific weight reported present menstrual dysfunction than athletes competing in sports focusing less on such factors and controls. On the basis of a comparison with a previous study, the prevalence of menstrual dysfunction was lower in 2003 than in 1993.