Abstract

In four ballet schools in the Newcastle region of NSW, Australia, the prevalence of menstrual dysfunction was examined in relation to changes in cardiorespiratory, endocrine and metabolic function. Thirty four dancers (mean age 15.4 +- 0.4 yr) and 31 non-dancers (mean age 15.5 +- 0.7 yr) were investigated by 1) questionnaire; 2) a test to determine peak exercise oxygen uptake; and 3) a prolonged exercise test (conducted at days 1-6 of the follicular phase of the menstrual cycle, or more than 90 days from the preceding menses, in amenorrhoeics). Seventy one percent of the dancers, including one primary and two secondary amenorrhoeics, reported menstrual irregularity, compared to 19 of the non-dancers. Forty seven percent of the dancers had a measured cycle length of greater than 38 days, compared to 3 of the non-dancers. Cardiorespiratory function was not notably different between the two groups, however, the endocrine profiles were clearly different; the dancers had decreased levels of circulating oestradiol (E2) and elevated testosterone (T), progresterone (P) and follicle stimulating hormone (FSH), both at rest and during exercise. The hormone levels suggest that the hypothalamus and pituitary functionally respond to the lowered E2 levels, and, by increasing gonadotrophin production, elevate T and P production, but not E2. The menstrual irregularity of the teenage ballet dancer is therefore possibly due to the changing E2/T ratio secondary to a block in the conversion process of androgen to oestrogen within the overy. Verf.-Ref.