Embryonic early-cleavage rate is decreased with aging in GnRH agonist but not inantagonist protocols.

ABSTRACT

PURPOSE: The aim of this study was to evaluate the correlation between embryonic early-cleavage status and the age of patients receiving either a GnRH agonist long protocol or a GnRH antagonist protocol. METHODS: This retrospective study included 534 patients undergoing a fresh cycle of oocyte retrieval and day-3 embryo transfer. Of the 534 patients treated, 331 received a GnRH agonist long stimulation protocol (GnRH agonist group) for ovarian stimulation and 203 patients received a GnRH antagonist protocol (GnRH antagonist group). RESULTS: By logistic regression analysis, the rate of embryonic early-cleavage was significantly decreased with increasing age of women in the agonist (P < 0.001) but not in antagonist groups (P = 0.61). Based on the results of this study, maternal age is a critical factor for embryonic early-cleavage in agonist protocol but not in antagonist protocol. The results also showed that early-cleavage embryos were of better quality and resulted in a higher pregnancy rate than late-cleavage embryos in the GnRH agonist group. However, embryo quality and pregnancy rate was not significantly different between early and late cleavage embryos in the GnRH antagonist group. CONCLUSIONS: We conclude that embryonic early-cleavage status is negatively correlated with aging in women receiving GnRH agonist long down-regulation but not in GnRH antagonist protocols. We also conclude that early cleavage of the zygote is not a reliable predictor for pregnancy potential using the GnRH antagonist protocol.