Impact of embryo replacement depth on in vitro fertilization and embryo transfer outcomes

Objective: To investigate the impact of embryo replacement depth on IVF and embryo transfer outcomes. Design: Retrospective analysis (May 2005 to November 2008) of 5,055 ultrasound-guided embryo transfers belonging to 3,930 infertile couples. The distance between the fundal endometrial surface and the catheter tip was measured and accordingly, patients were divided into five groups. Setting: Anatolia IVF Center, Ankara, Turkey. Patient(s): All patients enrolled in the IVF program undergoing embryo transfer. Intervention(s): No patient received any additional procedure or intervention. Main Outcome Measure(s): Clinical pregnancy rate (PR) and ongoing PR. Result(s): Mean total number of embryos transferred in groups 4 and 5 were significantly higher than in groups 2 and 3. Analysis of PRs and outcome of gestations in the five groups studied yielded similar PRs in all groups except for group 1. Conclusion(s): Pregnancy rates and ongoing PRs are higher if the embryos are replaced at a distance >10mm from the fundal endometrial surface. In addition because significantly more embryos were replaced in cycles where the transfers occurred at a distance of >20 mm, a distance >10 mm to <20 mm seems to be the best site for embryo transfer to achieve higher PRs. (Fertil Steril (R) 2010;94:1341-5. (C) 2010 by American Society for Reproductive Medicine.)