Ovulation triggering with GnRH agonist vs. hCG in the same egg donor population undergoing donor oocyte cycles with GnRH antagonist: a prospective randomized cross-over trial

To compare fertilization, implantation and pregnancy rates in donor oocyte cycles triggered for final oocyte maturation with either human chorionic gonadotropin (hCG) or gonadotropin releasing hormone (GnRH) agonist in the same donor population in two sequential stimulation cycles. Prospective randomized cross-over trial. Private infertility clinic. Eighty-eight stimulation cycles in 44 egg donors. Controlled ovarian hyperstimulation (COH) with GnRH antagonist protocol triggered with hCG or GnRH agonist (leuprolide acetate 0.15 mg) in the same egg donors in two consecutive cycles. The primary outcome measure was the proportion of mature and fertilized oocytes per donor cycle. Secondary outcome measures were implantation and pregnancy rates in the recipients and incidence of ovarian hyperstimulation syndrome (OHSS) in oocyte donors. The proportion of mature oocytes, fertilized oocytes and mean embryo scores were comparable between the two triggering agents. While implantation (36.53% vs, 32.93%), pregnancy (69.08% vs. 68.81%) and clinical pregnancy (41.3% vs. 40.2%) rates were comparable for the groups, the incidence of OHSS was significantly lower in GnRH than in hCG triggered cycles. Fertilization, implantation and pregnancy rates from donor oocytes stimulated with GnRH antagonist protocol were identical for donor cycles triggered with hCG and GnRH agonist. GnRH antagonist triggering in egg donors was associated with lower rates of OHSS.