Effect Of Cryopreservation Time On The Outcome Of Frozen-thawed Embryos Transplant

Objective:To explore different vitrification cryopreservation time on the outcome of cleaved embryo transfer.Methods:From January 2017 to December 2020,3 847 cases of vitrification cryo-resuscitation transfer of cleavage embryos,were performed in reproductive Medicine Center,The First Hospital of Shanxi Medical University.According to the cryopreservation time of embryos,the embryos were divided into 5 groups::≤ 1 year,(1,2] years,(2,3] years,(3,4]years and>4 years.Then,the differences in the general situation of patients in each group,embryo thawing and recovery and clinical outcomes were compared.Logistic regression analysis was used to analyze the effect of maternal age at oocyte retrieval and embryo transfer,embryo cryopreservation time,the number of transferred embryos or high-quality embryos on pregnancy outcome.Results:Endometrial thickness,the number of high-quality embryos,optimal embryo rate,the rates of embryo survival and intact embryo survival after thawing,biochemical pregnancy rate,miscarriage rate,ectopic pregnancy rate,multiple birth rate,birth boy rate,gestational age and neonatal weight had no statistical difference(P > 0.05).There were significant differences in the maternal age at oocyte retrieval and embryo transfer,the number of transferred embryos or high-quality embryos,optimal embryo rate,pregnancy rate and live birth rate(P<0.05).Logistic regression analysis showed that maternal age at oocyte retrieval or embryo transfer,and embryo cryopreservation time had no significant effect on pregnancy outcome(P>0.05),while there were significant differences in the number of transferred embryos and high-quality embryos(P<0.05).Conclusion:Cleavage stage embryo vitrification cryopreservation time has no significant effect on pregnancy outcome.