The effect of serum E2 level on endometrial transformation day on pregnancy outcome in HRT-FET cycle

Objective:To investigate the influence of serum E2 level on pregnancy outcome on endometrial transformation day in hormone replacement therapy-thawed embryo transfer(HRT-FET)cycle.Methods:Totally 834 embryo transfer cycles of cleavage stage treated by HRT-FET in Reproductive Center of First Affiliated Hospital of Hainan Medical College from December 2014 to December 2019 were analyzed retrospectively.Results:The number of transplanted embryos in group A was higher than that in group B,and the difference was statistically significant(P<0.05);The thickness and serum P level of endometrial transformation day in Group B were significantly higher than those in Group A(P<0.05);There was no significant difference in clinical pregnancy rate,implantation rate,abortion rate,ectopic pregnancy rate,biochemical pregnancy rate and live birth rate between Group A and Group B(P>0.05);There was no statistical difference in general data between group A1 and group A2,group B1 and group B2(P>0.05);There was no significant difference in clinical pregnancy rate,implantation rate,abortion rate,ectopic pregnancy rate,biochemical pregnancy rate and live birth rate between group B1 and group B2(P>0.05);The clinical pregnancy rate,implantation rate and live birth rate in group A2 were significantly higher than those in group A1(P<0.05).Conclusions:Endometrial type A or B has no significant effect on pregnancy outcome in hormone replacement therapy-thawed embryo transfer cycle.;In type A endometrium,the serum E2>827 pmol/L on the day of endometrial transformation is helpful to improve the pregnancy outcome of frozen-thawed embryo transfer.