Outcome of frozen-thawed blastocysts derived from gonadotropin releasing hormone agonist or antagonist cycles

Purpose: The aim of this retrospective study was to compare the outcome of frozen-thawed blastocysts derived from the cycles using controlled ovarian stimulation with GnRH agonists vs. GnRH antagonists. Methods: Survival, pregnancy and cumulative live birth rates in 231 freeze-thaw cycles derived from the GnRH agonist cycles (GnRH agonist group), and in 175 freeze-thaw cycles derived from the GnRH antagonist cycles (GnRH antagonist group) were compared. Results: In the GnRH agonist group significantly higher proportion of blastocysts survived the thawing procedure than in the GnRH antagonist group (86.1% versus 78.5%; p < 0.01). The differences in cumulative live birth rates did not differ significantly between the groups: in the GnRH agonist group the cumulative live birth rate was 16.5%, and in the GnRH antagonist group it was 14.2%. Conclusions: Frozen-thawed blastocysts derived from the GnRH agonist cycles have better survival rates and similar cumulative live birth rates than those derived from the GnRH antagonist cycles.