Association Between Endometrial/Subendometrial Vasculature and Embryo Transfer Outcome: A Meta‐analysis and Subgroup Analysis

Objectives To examine the association between endometrial/subendometrial vasculature and in vitro fertilization‐embryo transfer (IVF‐ET) and frozen embryo transfer (FET) outcomes. Methods A meta‐analysis of studies using endometrial/subendometrial 3‐dimensional ultrasound and power Doppler angiography was performed to examine the vascularization index (VI), flow index (FI), and vascularization‐flow index (VFI) in pregnant and nonpregnant women. Ten articles were analyzed, including 895 pregnant women and 882 nonpregnant women. Results A subgroup analysis of the measuring time showed that the endometrial VI (standardized mean difference [SMD], 0.57; 95% confidence interval [CI], 0.40, 0.74; P