An Analysis About Factors Affecting Clinical Pregnancy Outcome In Patients Undergoing HRT-FET

Objectives:To investigate the impact factors of clinical pregnancy outcome in patients undergoing hormone replace treatment to prepare the endometrium for frozen embryo transfer(HRT-FET)and thus provide scientific evidence for clinicians in infertile consulting.Methods:The clinical,laboratory and follow-up data of 6174 HRT-FET cycles from January 2010 to December 2015 in the Women's hospital,School of Medicine,Zhejiang University were collected.Impact factors of pregnancy and non-pregnancy groups were explored by univariate and logistic regression analysis.The differences and impact factors of clinical pregnancy rates between different years were compared.The correlation of serum estrodiol and progesterone level at the day of endometrial transformation and clinical pregnancy rates of infertile women were also investigated.Results:Among 6174 cycles,2586 cases(41.89%)had positive clinical pregnancy results,while3588 cases(58.11%)got negative results.These two groups had statistical significance differences in the infertile couples' age,years of infertility,serum basal FSH level,serum basal FSH/LH ratio and number of embryos transferred(P<0.05).By logistic analysis,we found that patients' age(OR=0.979,95%CI:0.965?0.992,P=0.002),years of infertility(OR=0.978,95%CI:0.979?1.009,P=0.023),the serum basal FSH/LH ratio(OR=0.877,95%CI:0.814?0.944,P=0.001)and the number of embryos transferred(OR= 1.448,95%CI:1.328?1.579,P<0.001)were the independent impact factors affecting the HRT-FET clinical pregnancy outcome.And then we divided all the cycles were divided into six groups according to the year of FET,and found statistical differences in the serum estrogen and progesterone level of the trigger day,thickness of endometrium at follicle achieving day,mature follicle number,high-quality embryo number,number of embryos transferred,thickness of endometrium and serum estrogen level at endometrial transformation day,embryo implantation rate and clinical pregnancy rate(P<0.05).Furthermore,all the cycles were divided into three groups according to the serum estrogen level at endometrial transformation day,but no significant difference was found in these three groups,despite of the negative correlation between the serum estrogen level and the clinical pregnancy rate.The thickness of endometrium at transformation day showed statistical difference(P<0.05).Analysis of 654 single embryo FET cycles with matched basic characteristics of patients showed that,only blastocyst transfer has significant impact on the clinical pregnancy outcome.Conclusions:1.Patients' age,years of infertility,serum basal FSH/LH ratio and number of embryo transferred have independent impact on HRT-FET clinical pregnancy outcome of infertile women.2.The clinical pregnancy rates between different years showed no difference,despite the decreasing tendency of the number of embryo transferred.3.Serum estrogen level at endometrial transformation day has no significant impact on the HRT-FET clinical pregnancy outcomes.