Effect Of Different Methods On The Outcome Of Freeze-thaw Transplantation In Patients With Thin Endometrium

Objective:the purpose of this study was to evaluate the effect of different endometrial preparation methods on the pregnancy outcome of thin endometrium during the freeze-thaw embryo transfer cycle.Methods:From August 2015 to August 2020,280 patients who underwent freeze-thaw cycle transplantation and whose endometrial thickness was less than 7mm on the day of embryo transplantation were selected and included in this study.The study was divided into three parts.Firstly,according to the endometrial preparation method,they were divided into natural cycle group(group A),ovulation induction cycle group(group B),hormone replacement therapy cycle group(group C),gonadotropin-releasing hormone agonist downregulation+hormone replacement therapy cycle group(group D).Secondly,they were re-divided into two groups according to the history of intrauterine adhesions,and then divided into two subgroups according to the endometrial preparation method:hormone replacement therapy and non-hormone replacement therapy.Thirdly,according to the endometrial thickness on the day of transplantation,the patients were divided into two groups:6mm<thickness<7mm and ≤6mm,and then they were divided into two subgroups:hormone replacement therapy and non-hormone replacement therapy according to the endometrial preparation method.Age,years of infertility,body mass index,basal follicle stimulating hormone,basal estradiol,the number of embryos transferred,the number of optimal embryos,endometrial thickness on transplantation day and pregnancy outcome were compared among all groups.Results:There was no significant difference in the general data between the four groups of endometrial preparation method(P>0.05).There were no significant differences in implantation rate,clinical pregnancy rate,abortion rate and live birth rate among the four groups(P>0.05).There were no statistically significant differences in endometrial thickness of patients with and without intrauterine adhesions(P>0.05).There were statistically significant differences in implantation rate,clinical pregnancy rate and live birth rate between patients with and without intrauterine adhesions(P<0.05).In the non-hormone replacement therapy,there was a significant difference in the implantation rate between the groups with and without the history of intrauterine adhesions(P<0.05).In hormone replacement therapy,there were significant differences in implantation rate and clinical pregnancy rate between groups with and without intrauterine adhesion history(P<0.05).There was no significant difference in pregnancy outcome between groups with different endometrial thickness range on transplantation day(P>0.05).There was no statistically significant difference in pregnancy outcome between hormone replacement therapy and non-replacement therapy under the same endometrial thickness range(P>0.05).There was also no statistically significant difference in pregnancy outcome between groups with different endometrial thickness under the same type of endometrial preparation regimen(P>0.05).Conclusion:1.The endometrial thickness of patients with thin endometrium was not affected by the natural cycle method,the ovulation induction cycle method,the hormone replacement therapy method and the downregulation+hormone replacement therapy method.2.In the freeze-thaw embryo transfer for thin endometrium patients,the implantation rate,clinical pregnancy rate and live birth rate of natural cycle method,ovulation induction cycle method and hormone replacement therapy method showed an increasing trend compared with the downregulation+hormone replacement therapy method,but there was no statistical difference.3.In the freeze-thaw embryo transfer for thin endometrium patients,the implantation rate of patients with no history of intrauterine adhesions was higher than that of patients with such history;Compared with thin endometrium patients without a history of intrauterine adhesions,hormone replacement therapy in patients with a history of intrauterine therapy was associated with a significantly lower abortion rate in freeze-thaw cycles.4.In the freeze-thaw embryo transfer for thin endometrium patients,there was no statistical difference in the effect of endometrial thickness ≤6mm and>6mm on pregnancy outcome.