The effect of vitrification freezing times on the pregnancy outcome of frozen embryo transfer
Objective To explore the effects of different vitrification freezing times on frozen embryo recovery and pregnancy outcomes.Method A retrospective analysis was conducted on the clinical data of 550 patients who met the inclusion criteria and under-went frozen embryo transfer.According to different vitrification freezing times of embryos,they were divided into 5 groups:A,B,C,D and E.Group A was 239 cases,with vitrification freezing time ≤3 months;Group B was 138 cases,with 3 months＜vitrification freezing time≤ 6 months;Group C was 74 cases,with 6 months＜vitrification freezing time ≤ 1 year;Group D was 75cases,with 1 year＜vitrification freezing time≤ 5 years;Group E was 24 cases,with vitrification freezing time＞5 years.The general clinical data,embryo recovery out-comes and clinical pregnancy outcomes of embryo transfer with different vitrification freezing times were compared.Results Compared with groups A,B,and C,the embryo survival rate and embryo integrity rate in group D were significantly reduced(P＜0.05).Compared with group A and B,the embryo survival rate,embryo integrity rate,and high-quality embryo rate after thawing/before freezing in group E were significantly reduced(P＜0.05).The embryo integrity rate of group E was significantly lower than that of group C(P＜0.05).The rate of high-quality embryos after thawing/before freezing in group E was significantly lower than that in group D(P＜0.05).There were no statistically significant differences in embryo implantation rate,clinical pregnancy rate,live birth rate,miscarriage rate,and premature birth rate among the groups after transferring high-quality embryos.After transferring high-quality cleavage stage embryos,the premature birth rate in group E was significantly higher than that in group B(P＜0.05).After transplantation of high-quality blas-tocysts,the premature birth rate in group C was significantly higher than that in group A(P＜0.05).Conclusion In the frozen embryo transfer cycle,a longer vitrification freezing time has a negative impact on the recovery outcome of embryos,but after transferring at least one high-quality frozen embryo,different vitrification freezing times have no effect on the clinical pregnancy outcome of embryo transfer.
万方数据
维普
