Comparison of different doses of gonadotropin-releasing hormone antagonist Cetrorelix during controlled ovarian hyperstimulation

Objective: To assess the minimal effective dose of a GnRH antagonist (Cetrorelix; Asta Medical, Frankfurt, Germany) to prevent premature LH surge in patients undergoing controlled ovarian hyperstimulation (COH) for assisted reproductive technologies. Design: In 69 patients COH was carried out with the association of hMG, starting on day 2 of the menstrual cycle, and a GnRH antagonist (Cetrorelix) was administered from day 6 of the hMG treatment (day 7 of the menstrual cycle) every day up to and including the last day of the hMG injection. In 32 and 30 patients, 0.5 mg and 0.25 mg of Cetrorelix were administered, respectively. Seven patients received 0.1 mg of Cetrorelix. Setting: Tertiary referral center. Result(s): No premature endogenous LH surge occurred in patients treated with 0.5 and 0.25 mg of Cetrorelix, and serum LH concentrations were maintained constantly low during the entire follicular phase in both groups. Follicle-stimulating hormone, LH, E 2 , and P expressed as area under the curve were similar in both groups. A premature LH surge (18 mIU/mL; conversion factor to SI unit, 1.00) with a concomitant P rise (1.7 μg/L; conversion factor to SI unit, 3.180) occurred in one of the seven patients treated with 0.1 mg Cetrorelix; therefore, treatment with this dose was discontinued. Conclusion(s): The minimal effective dose of Cetrorelix able to prevent premature LH surge in COH cycles is 0.25 mg administered daily.