Clinical outcomes using a flexible regimen of GnRH-antagonists and a 'step-up' of additional gonadotropins in donor oocyte cycles

To assess the impact of serum estradiol upon oocyte donor cycle stimulation characteristics and clinical outcomes using flexible GnRH-antagonist (GnRH-ant) with additional FSH supplementation.A retrospective chart review of 99 oocyte donor cycles using ovarian hyperstimulation with recombinant FSH (rFSH) and GnRH-ant was analyzed. Following discontinuation of oral contraceptives, controlled ovarian hyperstimulation was begun using rFSH (150-300 IU daily). GnRH-ant (ganirelix, Organon) and an additional 75 IU of FSH/day were begun when lead follicles were 13-14 mm in greatest diameter. Cycles were analyzed based on serum estradiol response following administration of GnRH-ant (Group 1: progressive rise and Group 2: no rise or a decline). Primary endpoints were cycle stimulation characteristics based on serum estradiol following GnRH-ant, clinical pregnancy and implantation rates.A decline in serum estradiol was seen after GnRH-ant administration in 45% of cycles. Clinical pregnancy rates per transfer (70 vs. 72%) and implantation rates (43 vs. 56%) were similar for each group.Flexible regimens of GnRH-ant even with additional rFSH in a 'step-up' fashion frequently result in a decline in serum estradiol during ovulation induction. While our study is non-randomized, it does not appear to result in any adverse affect in clinical outcomes in donor oocyte cycles.