Embryo afterloading: a refinement in embryo transfer technique that may increase clinical pregnancy

OBJECTIVE: Given the importance of ET technique during assisted reproductive technology cycles, we evaluated the effect of embryo afterloading subsequent to placement of the ET catheter on pregnancy rates vs. a standard direct ET. DESIGN: Retrospective cohort analysis. SETTING: University-based assisted reproductive technology program. PATIENT(S): Patients undergoing a fresh nondonor day 3 ET by a single provider over a 1-year period. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Clinical pregnancy. RESULT(S): One hundred twenty-seven patients met inclusion criteria, and the overall pregnancy rate was 46.5%. There was no difference between the two groups with respect to age, basal FSH, or number of embryos transferred. The ET method used was at the discretion of the provider. There was no difference between the two groups in the presence of blood on the transfer catheter. However, there were significantly more transfer catheters with mucus contamination in the direct transfer group (25.58% vs. 5.95%). The clinical pregnancy rate in the group with ET using the afterloading technique was higher than in the direct ET group (52.4% vs. 34.9%). CONCLUSION(S): There was a trend toward an increase in pregnancy rate when an embryo afterloading technique was used. A prospective randomized trial is needed to examine this issue.