Background: This randomized controlled trial was designed to evaluate whether a GnRH antagonist given every other day could prevent premature luteinization in women undergoing IVF/ICSI treatment.
Methods: A total of 73 women receiving ovulation stimulation IVF cycles with recombinant FSH were allocated randomly on cycle day 7 to GnRH antagonist ganirelix in multiple doses (0.25 mg each), either daily (n = 37 women, group 1) or every other day (n = 36 women, group 2) until the day of HCG administration.
Results: Serum FSH, LH, estradiol and progesterone values showed similar trends in the two groups. During FSH stimulation, 13 (35%) of the women in group 1 had premature LH rises (> or = 10 IU/l) of which eight (22%) were after the start of antagonist administration. In group 2 there were 14 (39%) LH rises during FSH stimulation of which 10 (28%) were after the start of antagonist administration. Luteinization (serum progesterone >2 ng/ml) occurred in only one woman in each group overall (3%). A significantly smaller total dose of the antagonist was used in group 2 than in group 1 (P < 0.001). The study did not have power to evaluate differences in total dose of FSH, number of oocytes recovered and clinical pregnancy rate, all of which appeared similar in the two groups.
Conclusions: Whether alternate day is as effective as daily administration of ganirelix in preventing premature luteinization should be addressed in a non-inferiority trial powered to evaluate live birth rate.