GnRH agonist long protocol vs. a single 3-mg gnRH antagonist: a comparison of 2 protocols for pituitary down-regulation in oocyte donor-controlled ovarian hyperstimulation cycles.

Objective: To compare ovarian stimulation outcomes for 2 protocols of pituitary down-regulation in a group of fertile women.

Study Design: Retrospective outcome analysis of 35 healthy oocyte donors participating in a university-affiliated in vitro fertilization donor program from 1999 to 2004. Consecutive donor cycles were grouped according to the agent used for down-regulation (n = 27 GnRH agonist, n = 31 GnRH antagonist). Statistical analysis was performed using ANOVA, chi2 and Wilcoxon Rank Sum tests.

Results: Neither gonadotropin dosage, days of stimulation or number of oocytes retrieved per treatment cycle were statistically different between groups. The only significant embryo quality parameter was more grade D embryos in the GnRH antagonist (0.4 +/- 0.6) vs. GnRH agonist arm (0.0 +/- 0.2). The number of embryos transferred was significantly greater for the GnRH agonist (2.7 +/- 0.5) than GnRH antagonist arm (1.0 +/- 0.5), whereas implantation and clinical pregnancy rates were not significantly different between groups. No patient experienced the ovarian hyperstimulation syndrome.

Conclusion: Since there was no significant difference in the biologic effects of the 2 protocols, the use of a 3-mg GnRH antagonist for down-regulation in a donor program is preferable to the long protocol because it requires only 1-2 injections for pituitary down-regulation.