Impaired estrogen-induced luteinizing hormone release in young women with anovulatory dysfunctional uterine bleeding.

Spontaneous ovarian activity, as reflected by the urinary excretion of total estrogen and pregnanediol measured serially (thrice weekly) over a period of 3-4 months, was studied in nine young women (15-27 yr old) with a history of dysfunctional uterine bleeding of at least 2-yr duration. Results were compared to those obtained in sex regularly menstruating women, aged 23-45 yr. All control women had ovulatory cycles, but seven of the nine patients with DUB failed to ovulate during at least three consecutive cycles. The profiles of urinary total estrogen excretion in these seven subjects were consistent with regular follicular development, but the follicular phase was prolonged and the amount of estrogen excretion increased, as compared to controls. In four of these seven patients, the endometrium had previously shown cystic glandular hyperplasia. Although the release of LH and FSH after injection of 50 micrograms synthetic LRH was normal, the surge of LH induced in response to exogenous estrogen (200 micrograms ethinylestradiol/day for 3 days) was significantly (P less than 0.005) lower in the patients (16.2 +/- 3.7 mU/ml) than that of control women )35.0 +/- 5.5 mU/ml). It is concluded that the failure to ovulate in young women with anovulatory dysfunctional uterine bleeding is due to inadequate release of LH in response to estrogen. The results support the hypothesis that the basic defect in these women may be a decrease of hypothalamic sensitivity to positive feedback.