Objective To systematically review the endometrial receptivity evaluated by transvaginal ultrasound and predict the clinical pregnancy outcome of in vitro fertilization-embryo transfer (IVF-ET). Methods PubMed, The Cochrane Library, EMbase, Web of Science, CNKI, WanFang Data and VIP databases were electronically searched to collect studies on transvaginal ultrasound evaluation of endometrial receptivity to predict the clinical pregnancy outcome of IVF-ET from inception to December 1st, 2021. Two researchers independently screened literature, extracted data and evaluated the risk of bias of the included studies. RevMan 5.4 software and Stata 16.0 software were used to perform meta-analysis. Results A total of 24 cohort studies and 1 case-control study were included. The total sample size was 6 632 cases, including 3 340 in non-pregnancy group and 3 292 in pregnancy group. The results of meta-analysis showed that there was no difference in endometrial volume (MD=?0.11, 95%CI ?0.33 to 0.11, P=0.34) or uterine artery S/D (MD= ?0.04, 95%CI ?0.17 to 0.09, P=0.55) between the two groups. The endometrial thickness measured on human chorionic gonadotrophin (HCG) day in the non-pregnant group (MD=?0.48, 95%CI ?0.77 to ?0.18, P=0.001) was thinner than that in the pregnant group. On embryo transfer (ET) day, uterine artery pulsatility index (PI) (MD=0.08, 95%CI 0.02 to 0.15, P=0.01) and resistance index (RI) (MD=0.01, 95%CI 0.01 to 0.01, P<0.000 01) were higher than those in the pregnancy group. Conclusion Endometrial volume and uterine artery S/D measured during IVF-ET were not correlated with clinical pregnancy outcome, while endometrial thickness measured on HCG day and uterine artery PI and RI measured on ET day were correlated with clinical pregnancy outcome. Transvaginal ultrasound evaluation of endometrial receptivity has a certain predictive value for clinical pregnancy outcome of IVF-ET. Due to the limited quality and quantity of included studies, more high-quality studies are needed to verify the above conclusion.
