Triggering of ovulation in human menopausal gonadotrophin-stimulated cycles: comparison between intravenously administered gonadotrophin-releasing hormone (100 and 500 μg), GnRH agonist (buserelin, 500 μg) and human chorionic gonadotrophin (10 000 IU)

We studied the peri-ovulatory and luteal phases in 38 human menopausal gonadotrophin (HMG)-stimulated cycles, in which ovulation was triggered with four different i.v. bolus ovulation triggers: 100 μg gonadotrophin-releasing hormone (GnRH; group A, n = 9), 500 μg GnRH agonist (GnRHa; group B, n = 10), 10 000IU human chorionic gonadotrophin (HCG; group C, n = 10) and 500 μg GnRH (group D, n = 9). Endogenous luteinizing hormone (LH) surges occurred in all cycles of groups A, B and D. The rise was slowest but highest in group B (P < 0.0001) and lowest in group A. Although the t0 serum oestradiol values were similar in all groups, day +8 oestradiol and day +4 and +8 progesterone concentrations were higher in group C (P < 0.05). At day +4 and +8, serum LH concentrations were lowest (P < 0.01) but follicle stimulating hormone (FSH) concentrations were higher. Clinically, day +8 luteal scores showed a more conspicuous degree of ovarian hyperstimulation in the HCG group (P = 0.0292). Luteal insufficiency, defined as cycles with progesterone concentrations of