Pituitary gonadotrophin secretory capacity during the luteal phase in superovulation using GnRH-agonists and HMG in a desensitization or flare-up protocol.

Pituitary gonadotrophin reserve and basal gonadotrophin secretion were tested during the luteal phase in women superovulated with buserelin/human menopausal gonadotrophin (HMG) in a desensitization (n = 17) or flare-up protocol (n = 7). In the desensitization protocol the luteinizing hormone-releasing hormone (LHRH) stimulated serum LH and follicle stimulating hormone (FSH) concentrations remained impaired at least until day 14 after arrest of the agonist. In the flare-up protocol basal and stimulated LH secretion was still abnormal on days 14 and 15 after human chorionic gonadotrophin (HCG) injection. Normal basal serum FSH concentrations were measured at the end of the luteal phase in the flare-up protocol, but the response of FSH to LHRH injection was still subnormal. We conclude that gonadotrophin function remained impaired until the end of the luteal phase after desensitization and flare-up GnRH-agonist and HMG stimulation protocols. Corpus luteum stimulation with exogenous HCG or substitution therapy using natural progesterone are required to prevent the possible negative effects resulting from pituitary dysfunction after GnRH-agonist treatment.