Comparison of vitrification and slow-freezing of human day 3 cleavage stage embryos:postvitrification development and pregnancy outcomes / 中华妇产科杂志

ABSTRACT

Objective To compare the effects of vitrification with slow-freezing on the developmental ability of day 3 cleavage stage embryos.Methods Patients who had no less than 4 high quality embryos were included in this study.These embryos were cryopreserved using the methods of vitrification or slow-freezing.In the eryopreserved embryo transfer cycles,the embryos which were cryopreserved using one of the methods were chosen randomly.The developmental ability of embryos was compared between these two groups.Results A total of 80 patients were included in this study with 160 embryos.In the group of slow-freezing,73(91%)embryos were survived and achieved 15(38%)clinical pregnancies.Among these,3 were twins and the implantation rate was 25%(18/73).In the group of vitrification,71(89%)embryos were survived and achieved 19(48%)clinical pregnancies.Among these, 9 were twins and the implantation rate was 39%(28/71),which was significantly higher than the slow- freezing group(P