Effects of cumulus cells on vitreous cryopreservation of human mature oocytes and clinical pregnancy outcomes

The purpose of this study was to explore the effects of cumulus cells on vitreous cryopreservation of human mature oocytes and clinical pregnancy outcomes. The study was divided into group A (cumulus cells were removed from the oocytes before freezing) containing 24 participants and 193 oocytes and group B (cumulus cells were retained with the oocytes before freezing) containing 26 participants and 240 oocytes. Based on no significant differences in age, duration of infertility, infertile causes, and number of retrieved oocytes between both groups when oocytes were retrieved from infertile women, we found that the survival rate of post thaw oocytes (88% vs 58%), cleavage rate (80% vs 56%), and high-quality embryo rate (75% vs 59%) were significantly higher in group B than in group A. Under the conditions that there were no significant differences between the 2 groups in the general status of the participants undergoing embryo transfer, the embryo implantation rate (37% vs 15%) and the clinical pregnancy rate (50% vs 17%) were significantly higher in group B than in group A, all with Ps < .05. We conclude that the retention of cumulus cells can improve the developmental competence of vitrified-thawed human mature oocytes and clinical pregnancy outcomes.