Efficacy of Gonadotropin-releasing Hormone Antagonist and Agonist in Controlled Ovarian Hyperstimulation in IVF-ET Patients with Expected Normal Ovarian Response.

Objective : To assess the efficacy of GnRH antagonist in controlled ovarian hyperstimulation (COH) for IVF-ET compared with GnRH agonist in infertile patients who are expected to have normal ovarian response. Methods : This study reviewed 105 cycles of 105 women who underwent IVF-ET for the first time in SNUH from January, 2001 to October, 2003. In the study group (n=51), a daily dose of 0.25 mg of GnRH antagonist (cetrorelix or ganirelix) was administered beginning when leading follicles reached mean diameter of 13-14 mm and continued until the day of hCG injection. In the control group (n=54), patients were first desensitized with GnRH agonist (triptorelin) long protocol, which was continued during the gonadotropins treatment until the day of hCG injection. The outcome parameters of COH and IVF-ET were compared retrospectively between the two groups. Statistical analysis was performed using Student's t-test for the comparison of means, and the chi-square test where appropriate. Statistical significance was defined as p812.3 IU vs. 2420.2839.2 IU)and the duration of COH (8.92.1 days vs. 10.91.6 days). The mean serum level of estradiol and endometrial thickness on hCG day were significantly lower in the study group. Number of embryos transferred and CES (cumulative embryo score) were significantly lower in the study group compared to the control group. However there were no significant differences in the number of oocytes retrieved, the fertilization, implantation, and clinical pregnancy rates, and the incidence of OHSS between the two groups. Conclusion : For patients who are expected to have normal ovarian response, a GnRH antagonist multiple dose protocol in flexible fashion can be used as a protocol of choice in COH for IVF-ET. This protocol showed comparable pregnancy rate as GnRH agonist long protocol. However, the mean number of gonadotropin ampules administered and the mean number of stimulation days were significantly less in the GnRH antagonist group optimizing the convenience for the patients.