Exercise-induced menstrual dysfunction.

Menstrual cycle changes associated with vigorous exercise can range widely. They may be only subtle abnormalities, ranging from delayed onset of spontaneous menses or anovulatory cycles to loss of spontaneous menses. They may be more serious, however. Significant adverse bone mineral changes, resulting in clinically significant osteoporosis and fractures, may occur concomitantly with exercise-induced menstrual dysfunction.