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

PurposeThe 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.MethodsSurvival, 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.ResultsIn 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%.ConclusionsFrozen-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.