Endometrial volume measured on the day of embryo transfer is not associated with live birth rates in IVF: A prospective study and review of the literature.

Objective: To evaluate the effect of endometrial volume (EV) on the live birth rates (LBR)s in fresh or frozen embryo transfer (ET) cycles.

Material And Methods: This is a prospective study including all women who underwent a fresh or frozen single blastocyst transfer between January 2017 and September 2018 in a university affiliated private hospital. Patients with advanced age (>42years), congenital uterine anomalies, endometrial or myometrial abnormalities, those with a difficult ET, those with only poor-quality blastocysts available for transfer, those in whom an optimal 3D TVUS image could not be obtained and those who were lost to follow-up were excluded. Endometrial volume was assessed using Virtual Organ Computer Aided Analysis program immediately prior to ET by two different observers using a standardized technique. The association of ET outcome and EV was evaluated by receiver operating characteristics (ROC) curve and logistic regression analysis.

Results: A total of 142 patients were included in the final analysis. Patients were grouped according the EV percentiles (p); 5thp (1.7 mL), 10thp (2.2 mL), 25thp (2.9 mL), 50thp (4.3 mL) and >75thp (>5.3 mL) groups. ROC curve analysis was not predictive of LBRs, with an AUC (95 % CI) = 0.48 (0.38-0.58). There was no critical threshold, below which pregnancy was unlikely to occur. No significant association was observed between EV and any of the evaluated clinical outcomes.

Conclusion(s): When controlled for potential confounders, EV assessed by 3D TVUS is not a useful tool for predicting pregnancy in single blastocyst ET cycles.