High doses of gonadotrophin-releasing hormone antagonist in in-vitro fertilization cycles do not adversely affect the outcome of subsequent freeze-thaw cycles

The clinical application of gonadotrophin-releasing hormone (GnRH) antagoni sts instead of GnRH agonists, to prevent spontaneous premature luteinizing hormone surge during ovarian stimulation for assisted reproduction treatmen t has been advocated. A recent, double-blind, dose-finding study, including six dosages of the GnRH antagonist ganirelix, in women undergoing ovarian stimulation with recombinant follicle stimulating hormone (FSH), has indica ted that high doses of GnRH antagonist (I or 2 mg once daily) are associate d with a low implantation rate. This follow-up study reports on the pregnan cy rate after replacement of cryopreserved embryos obtained in stimulation cycles of the above-mentioned trial. Ovarian stimulation was initiated on d ay 2 of the cycle, with daily injections of 150 IU recombinant FSH, Ganirel ix (0.0625, 0.125, 0.25, 0.5, 1.0 or 2.0 mg) was administered once daily fr om stimulation day 6 onwards, up to and including the day of human chorioni c gonadotrophin. Retrieved oocytes were fertilized by in-vitro fertilizatio n (IVF) or intracytoplasmic sperm injection and a maximum of three fresh em bryos was transferred. Excess embryos were frozen, and subsequently used in either natural or programmed cycles. Until June 1998, 11 ongoing pregnanci es (12-16 weeks after embryo transfer) were achieved from 46 cycles in whic h embryos had been first frozen (23.9% per transfer). Six of these 11 patie nts had been treated with a high dose of ganirelix (1.0 or 2.0 mg) during t he IVF cycles in which the embryos mere obtained, In conclusion, our data s uggest that high dosages of ganirelix do not adversely affect the potential of embryos to establish clinical pregnancy in freeze-thaw cycles.