Further characterization of the luteal phase inadequacy after gonadotrophin-releasing hormone agonist-induced ovulation in gonadotrophin-stimulated cycles.

To characterize further the luteal phase ensuing gonadotrophin-releasing hormone agonist (GnRHa)-induced ovulation in exogenous gonadotrophin-stimulated cycles, plasma progesterone concentrations on luteal days +2 and +8 were determined in 20 patients (group 1) receiving one s.c. 0.5 mg injection of the GnRHa leuprolide acetate and in 10 patients (group 2) receiving two doses 12 h apart in multifollicular cycles stimulated with highly purified follicle-stimulating hormone (FSH). The patients received luteal support with micronized vaginal progesterone from day +2 (after sampling for plasma progesterone determination) until the onset of menses. The duration of the luteal phase was also assessed. As a control group, we included five fertile women who underwent plasma progesterone determinations on days +2 and +8 according to the luteinizing hormone peak in their spontaneous ovulatory cycles. On day +2, plasma progesterone concentrations were significantly higher in groups 1 and 2 than in the controls. However, on day +8, the mean plasma progesterone concentration and the average progesterone concentration per pre-ovulatory follicle were significantly higher in the control women than in groups 1 and 2. Furthermore, 13 patients (65%) in group 1 and seven patients (70%) in group 2 had plasma progesterone concentrations < 2 SD below the mean value obtained in the controls on that post-ovulatory day. Percentage increments in the plasma progesterone concentration from day +2 to day +8 were significantly lower in groups 1 and 2 than in the control group of spontaneous ovulatory cycles.(ABSTRACT TRUNCATED AT 250 WORDS)