Effectiveness of a low gonadotrophin-releasing hormone antagonist dose in preventing premature luteinizing hormone rise during controlled ovarian stimulation.

The current prospective randomized study was designed to test the efficacy of a low dose (0.125 mg/day) of the gonadotrophin-releasing hormone antagonist cetrorelix in preventing premature luteinizing hormone (LH) rise during controlled ovarian stimulation in comparison with the standard dose of 0.25 mg/day. Ovarian stimulation was started with 225 IU of recombinant follicle stimulating hormone (FSH) on day 2 of the menstrual cycle. Cetrorelix was injected daily from day 6 of gonadotropin administration. Blood was sampled from each woman on day 3 of ovarian stimulation and then daily from day 5 onward up to human chorionic gonadotropin administration for analysis of FSH, LH, progesterone, and estradiol. LH rise was defined as serum LH ≥ 10 mIU/ml. There were 40 patients receiving cetrorelix at 0.25 mg/day and 36 patients receiving cetrorelix at 0.125 mg/day. Premature LH rise was recorded in 10% of patients injecting antagonist at 0.25 mg/day and in 14% of patients administered with antagonist at 0.125 mg/day. These frequencies did not differ statistically. In conclusion, our results suggest that a cetrorelix dose of 0.125 mg/day is effective as the standard dose (0.25 mg/day) in preventing premature LH rise during controlled ovarian stimulation.