Profiles of selected hormones during menstrual cycles of teenage athletes.

Concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P), 17 alpha-hydroxyprogesterone (17 alpha OHP), 17 beta-estradiol (E2), and prolactin (HPr) were monitored for one complete menstrual cycle in teenage swimmers, a gynecologically age-matched control group, and a group of fertile adult women. The swimmers experienced anovulatory menstrual cycles. The time from the LH surge to the onset of menses ("luteal" phase) was very short in the swimmers (4.5 +/- 0.6 days) in comparison with the lengths of these phases in the adults (13.4 +/- 1.7 days; P less than 0.05) and in the control group (7.8 +/- 3.0 days; P less than 0.05). In the follicular phase the swimmers' LH concentration was elevated and their FSH concentration was depressed in comparison with each of the other groups (P less than 0.05). Luteal phase FHS, P, E2, and 17 alpha OHP were also lower in the swimmers (P less than 0.05), as was HPr (0.05 greater than P less than 0.10). Gonadotropin concentrations and luteal phase P concentrations were not different (P greater than 0.05) in the adults and the control group. The present findings indicate that the corpora lutea in the swimmers were not functioning properly. It is likely that the swimmers' strenuous daily 2-4 h training regimen is implicated.