ABSTRACT
OBJECTIVE: To compare the clinical outcomes of GnRH antagonist (cetrorelix(R)) with those of conventional GnRH agonist for down-regulation in assisted reproductive cycle. Materials and Method: Ninety-nine women undergoing IVF or ICSI were treated with either GnRH antagonist (cetrorelix(R)) or GnRH agonist (Lucrin(R)) for pituitary down regulation. The patient characteristics, basal hormone profile and IVF outcome were compared. RESULTS: There were no significant differences in age and duration of infertility between two groups. E2 (pg/mL)/LH (mIU/mL)/FSH (mIU/ mL) on the 3 day of menstrual period as a baseline were also not significantly different between two groups. The number of hMG amples administered (30.5+/-11.2 versus 47.6+/-16.4 ample/cycle) and the duration of stimulation (11.0+/-1.7 versus 14.1+/-2.2 days) were significantly lower in the cetrorelix(R) group. There were no significant differences in the fertilization and pregnancy rates, the number of embryo transferred, the number of mature oocyte and the number of embryo obtained between two groups. CONCLUSION: The cycles using an antagonist protocol shows a shorter duration of stimulation with comparable outcomes with few injections than those with an agonist protocol. GnRH antagonist can be effectively used as GnRH agonist for pituitary down regulation in IVF-ET cycles.