Different gonadotropin and leuprorelin ovulation induction regimens markedly affect follicular fluid hormone levels and folliculogenesis

Objectives: To clarify the endocrine mechanisms underlying the outcome of different ovulation induction regimens with gonadotropins and GnRH agonists (GnRH-a). Design: Prospective study. Setting: Reproductive Endocrinology Center, University of Bologna. Patients: Forty eumenorrheic women randomly assigned to four groups of 10 subjects each. Interventions: Ovulation induction regimens: group A, purified FSH only; group B, purified FSH and flare-up GnRH-a; group C, purified FSH and long GnRH-a; and group D, hMG and long GnRH-a. Main Outcome Measures: Pelvic ultrasound and hormone levels in daily serum samples and in follicular fluid drawn immediately before hCG administration. Results: Exogenous gonadotropin dose did not differ among groups. Group B had fewer preovulatory follicles than group C. Group B had higher serum LH, FSH, E(2), P, T, and follicular fluid LH, E(2), T, and alpha-inhibin than groups C and/or D. Groups C and D did not differ. Conclusions: Long GnRH-a regimens improved follicle yield and the endocrine milieu in spite of comparable exogenous gonadotropin dose and lower serum FSH and thus appear to be preferable in assisted reproduction. Reduced folliculogenesis found in flare-up GnRH-a regimens could be mediated by the atretic effects of high intraovarian androgens. Efficacy of purified FSH and hMG was comparable.