Ovarian response and follicular development for single-dose and multiple-dose protocols for gonadotropin-releasing hormone antagonist administration

Objective: To determine the efficiency of a single-dose and a multiple-dose protocol for GnRH antagonist administration. Design: Randomized clinical trial. Setting: University hospital, tertiary medical center. Patient(s): Sixty-one patients undergoing controlled ovarian stimulation (COS) and IVF/ICSI. Intervention(s): COS with either a multiple-dose (MD) or a single-dose (SD) protocol for GnRH antagonist (cetrorelix) administration, or with a long protocol (LP) for GnRH agonist (buserelin) administration, followed by oocyte retrieval, IVF/ICSI, and embryo transfer. Main Outcome Measure(s): Follicular development and serum levels of E₂ and LH. Result(s): The SD protocol for cetrorelix was associated with a more reduced level of follicular development, lower levels of serum estradiol on the day of HCG administration, and a more reduced number of zygotes than the LP for buserelin. The pregnancy and implantation rates did not differ significantly for the three study groups. Conclusion(s): The MD and SD GnRH antagonist protocols were effective for preventing LH surge and appear to elicit an equivalent pregnancy rate to that corresponding to a LP GnRH agonist. In terms of follicular development, the SD protocol requires further modification, including flexible scheduling or possibly a small reduction of the dosage of the administered cetrorelix.