Uterine cavity shape and the best site for embryo transfer

ObjectiveTo determine the best site for embryo placement in uterine cavities of varying shapes.MethodIn this prospective investigation, 638 embryo transfers were allocated to two groups: for group 1 (n = 558) embryos were transferred into uterine cavities of normal shape; for group 2 (n = 80) embryos were transferred into uterine cavities of abnormal shape. The uterine cavity was divided into 3 equal regions: upper, middle, and lower. Pregnancy outcomes for placements in each region were compared within and between the 2 groups.ResultsNo significant differences were found in rates of pregnancy or implantation among the 3 regions in group 1. In contrast, the implantation rate in group 2 was highest when embryos were placed in the middle region of the uterine cavity: 28.8% compared with 6.8% and 8.3% for the upper and lower regions, respectively (P < 0.05).ConclusionFor the normal uterine cavity, pregnancy outcomes do not depend on embryo placement. However, for uterine anomalies, embryo placement in the middle region of the uterine cavity gave the best outcome.