The Role of Endometrial Volume and Endometrial and Subendometrial Vascularization Parameters in a Frozen Embryo Transfer Cycle

The role of three-dimensional power Doppler ultrasonography of the endometrium in assisted reproduction is still far from clear. In this retrospective cohort study, transvaginal three-dimensional power Doppler examinations were performed 30 min before frozen–thawed embryo transfer. After pregnancy tests, two cohorts were established: P (pregnant, n = 31) and NP (nonpregnant, n = 31). The study only included nullipara with no uterine abnormalities who were undergoing infertility treatment at the Department of Gynecology, Obstetrics and Gynecological Endocrinology, Kepler University Hospital, Linz, Austria. The main outcome measures were the vascularization flow index (VFI), flow index (FI), and vascularization index (VI) in the endometrium/subendometrium, assessed using Virtual Organ Computer-aided AnaLysis (VOCAL™), and the endometrial volume. A total of 62 patients were enrolled in the study, forming two cohorts (pregnant, P; nonpregnant, NP). There were no significant differences between the two cohorts...