O-149 Endometrial thickness as a predictor of live birth and perinatal outcomes following oocyte donation

Abstract Study question Does endometrial thickness (EMT) predict the occurrence of live birth following oocyte donation? Summary answer Our study found that EMT is predictive of live birth in oocyte donation. What is known already EMT is a widely used surrogate marker of endometrial receptivity and is believed to be associated with in vitro fertilization pregnancy outcomes. However, the evidence thus far is mixed, with many studies (and even meta-analyses) suggesting that EMT may have little/no predictive value. One potential reason for the heterogeneity in results may be that most studies assessed mostly fresh autologous embryo transfers, without accounting for embryo quality nor the effect exogenous ovarian stimulation may have on endometrial receptivity and subsequent pregnancy/perinatal outcomes. Moreover, most subcategorized EMT to facilitate interpretation, which may have inadvertently introduced bias to the analyses. Study design, size, duration This retrospective, multicentre, cohort study analyzed all single blastocyst embryo transfers following oocyte donation from 2010-2019 subdivided into regular intervals of EMT (