Factors Influencing the Live Birth Rate of Fresh Embryo Transfer in Infertile Women with Endometrial Cavity Fluid: A Case Control Study

Abstract Background: The pregnancy outcome of infertile patients with endometrial cavity fluid undergoing fresh embryo transfer is controversial. We aimed to build a logistic regression model including age, ovarian function and ovarian stimulation protocols to predict the live birth rate of fresh embryo transfer in patients with endometrial cavity fluid.Methods: Patients underwent in vitro fertilization/intracytoplasmic sperm injectio were selected from January 2014 to September 2020 in the Reproductive Hospital affiliated to Shandong University, and the presence of endometrial cavity fluid was indicated by ultrasound before fresh embryo transfer. A total of 2383 patients with endometrial cavity fluid suggested by ultrasound before fresh embryo transfer were enrolled in this study. Clinical and laboratory parameters that may influence live birth rate were analysed. Univariate, multivariate analysis and Receiver operating characteristic curve were conducted to evaluate the relationship between the predictors and live birth rate.Results: The overall live birth rate was 1224/283 (51.38%), multivariate logistic analysis indicated that only transfer 2 embryos increased the probability of live birth (aOR: 2.274; 95%CI: 1.539- 3.361; P<0.01), other factors will reduce the chance of live birth, age≥35 (aOR: 0.509; 95%CI: 0.410-0.632; P<0.01), history of endometritis (aOR: 0.236; 95%CI: 0.076-0.729; P=0.012), Gonadotropin start-up dose>150IU (aOR: 0.785; 95% CI: 0.635-0.970; P=0.025), endometrial thickness on trigger day<8mm (aOR：0.286；95%CI：0.166-0.492；P<0.01), the gonadotropin releasing hormone agonist short regimen (aOR:0.611; 95%CI: 0.467-0.799; P<0.01). In addition, we found that hydrosalpinx did not significantly affect the live birth rate after fresh embryo transfer in endometrial cavity fluid patients.Conclusions: For infertile patients with endometrial cavity fluid before fresh embryo transfer, age <35 years, endometrial thickness ≥8mm on trigger day and transfer two embryos might obtain better pregnancy outcomes, and history of endometritis, gonadotropin releasing hormone agonist short regime and Gonadotropin start-up dose >150IU might be opposite.