Gonadotropin-releasing hormone agonist versus human chorionic gonadotropin as a trigger of ovulation in polycystic ovarian disease gonadotropin hyperstimulated cycles

Objective: To compare the use of GnRH agonist (GnRH-a) versus hCG in triggering the follicular rupture in patients with polycystic ovarian disease (PCOD) in whom ovulation was induced by gonadotropins. Design: Polycystic ovarian disease gonadotropin hyperstimulated cycles outcome was investigated in a prospective study. Patients and Interventions: Thirty-three PCOD patients (40 cycles) with gonadotropin-induced mild to moderate degree of ovarian hyperstimulation received 5,000 IU IM hCG or 200 g SC GnRH-a. A subgroup of GnRH-a-treated patients received P for luteal support. Five GnRH- a-treated patients underwent a GnRH test during luteal phase. Main Outcome Measures: Echographic and endocrine characteristics both during the therapy and the luteal phase. Results: There was a similar percentage of ovulation and pregnancy rate in both groups of patients. The ovarian enlargement during the luteal phase in the GnRH-a-treated patients was lower than in the hCG group. Progesterone plasma levels (at midluteal phase) and the length of luteal phase was significantly lower in GnRH-a-treated patients with respect to the hCG-treated group. These differences disappeared in patients receiving luteal support. After GnRH injection, LH secretion decreased in GnRH-a- treated patients with respect to controls; however, corpus luteum was able to respond with a normal increase of P production. Conclusion: The GnRH-a appears to be an effective alternative to hCG for inducing the follicular rupture in stimulated cycles in women who are at risk for developing ovarian hyperstimulation syndrome. However, GnRH-a administration can induce short luteal phase. This defect may be ascribed to the pituitary desensitization rather than to a direct effect on corpus luteum. Luteal phase support is needed to prevent luteal phase deficiency.