Effect Of Endometrial Preparation Protocols On Pregnancy Outcome For Patients With Thin Endometrium

BackgroundThe incidence of infertility has been rising year by year in women of childbearing year.With the fast development of the advanced cryo-preservation techniques,the proportion of frozen-thawed embryo transfer(FET)have expanded by degrees.FET play an important role on improving cumulative pregnancy rate,reducing embryo tranfer number,lowering multiplets rate,decreasing cost of treatment and preventing ovarian hyperstimulation syndrome(OHSS).Endometrial receptivity(ER),embryo quality,embryo development and endometrial synchrony are important factors affecting the prognosis of FET.Along with the development of laboratory technique and assisted reproductive technology(ART),embryo equality and endometrial synchrony has been monitoring and controllable little by little.Endometrial receptivity is becoming the focus of assisted reproduction.However,endometrial thickness(EMT)is a essential indicator for judging endometrial receptivity(ER).Current research suggests that EMT during the menstrual cycle reflexs the functional status of the endometrium,to a certain extent.Thin endometrium will affect ER and a decrease in embryo implantation rate,leading to a decrease in live birth rate,ultimately.In women receiving ART,about 2.4%of the cycles is with thin endometrium.Nowadays,the common endometrium preparation protocols include natural cycles(NC),cycle with ovulation induction(OI),and hormone replacement therapy(HRT)cycle.Previous studies have suggested that there were no statistic difference in live birth rates,miscarriage rates and clinical pregnancy rates when the EMT on Progesterone conversion day is in the normal range.While,when it comes to the thin endometrium(TE)patients,the infulence of different endometrium preparation protocols is still unknown.ObjectiveThe aim of this study was to compare the clinical outcomes of different methods of endometrial preparation in women with TE.MethodThe study included 811 thin endometrium cycles that patients received FET treatment after In vitro fertilizition(IVF)/Intracytoplasmic sperm injection(ICSI)/Preimplantation genetic diagnosis(PGD)/Preimplantation genetic screening(PGS)cycles in Center for Reproductive Medicine,Shandong University from January,2015 to October,2019.The patients were divided into three groups according to the protocol for preendometrial preparation of FET’s:OI group(n=274),NC group(n=183)and HRT group(n=353).The main pregnancy outcome was term delivery rate and preterm delivery rate.The minor pregnancy outcome included clinical pregnancy and miscarriage rates,etc.Data analysis included A chi-aquare,ANOVA and binary logistic analysis.ResultIn general,the age of NC group(33.12±3.95)is older than HRT group(32.19±3.86)(p=0.028),The BMI of NC group(22.59±2.96)is lower than HRT group(23.36±3.36)(p=0.015).There were no other statistically outstanding divergences in clinical features between the three groups,such as number of transplant cycles,number of embryo transferred,EMT on Progesterone conversion day and quality embryo ratio.For patients younger than 35 years old,three endometrial preparation methods shows similar pregnancy outcomes.For patients not younger than 35 years old,the term delivery rate for OI\NC\HRT group is 21.18%、16.46%、26.72%,HRT group is apparently higher than NC group(p=0.01)..Preterm delivery rate and the minor pregnancy outcome were no statistical significance among three groups.ConclusionFor elderly patients(≥ 35),HRT group has higher term delivery rates for patients older than 34 years old.For patients under 35,three different types of endometrial preparation methods for FET cycles appear to be equally effective in terms of pregnancy outcome.