Reproductive system function in women cross-country runners

Abstract

The incidence and etiology of altered menstrual cycle function in women engaged in endurance athletic activities were investigated by studying endocrine, anthropometric and training parameters in 41 cross-country runners. The prevalence of altered menstrual cycle patterns was significantly higher in the subjects than in college-aged women; 49% reported normal cycles and 51% were either oligomenorrheic (46%) or amenorrheic (5%). No significant differences between those reporting normal menstrual cycling (N) and those reporting oligo/amenorrhea (O/A) were found in the following areas: number of miles run/wk, number of yr of training, age when training began, sum of skinfold thicknesses, somatotype, or post-exercise levels of growth hormone, prolactin or hematocrit. However, a difference (P < 0.05) was found in the mean age of menarche (N = 12.9 .+-. 0.3 yr; O/A = 14.3 .+-. 0.5 yr). In addition, more O/A (68%) than N (42%) began training in the year of or prior to menarche. Evaluation of 7 runners from one school who qualified for the national meet (1 amenorrheic, 5 oligomenorrheic and 1 normal) revealed that the basal estrogens, progesterone, prolactin and thyroid hormone levels were normal and that there were normal luteinizing hormone and FSH responses to synthetic gonadotropin-releasing hormone (GnRH). These data are consistent with an alteration of hypothalamic-pituitary-ovarian function above the level of the pituitary.