Oocyte morphology does not affect post-warming survival rate in an egg-cryobanking donation program

Abstract

To evaluate whether oocyte dysmorphisms affect oocyte survival rates in an egg-cryobanking donation program. This study included 54 patients undergoing intracytoplasmic sperm injection. A total of 415 metaphase II oocytes were vitrified using the Cryotop method. Oocyte morphology was assessed immediately prior to oocyte vitrification under 400× magnification. The influence of dysmorphisms on post-thaw survival rates was assessed using regression analysis. Results were considered to be significant at the 5% critical level. Oocyte survival rate was not affected by the presence of the following analysed oocyte abnormalities: increased cytoplasmic granularity, vacuoles in the ooplasm, aggregates of smooth endoplasmic reticulum in the ooplasm, large perivitelline space size, perivitelline space granularity, fragmented first polar body and zona pellucida abnormalities. Oocyte morphology, observed prior to vitrification, does not predict post-warming survival. The non-invasive identification of predictive markers for oocyte survival potential remains a difficult task.