Optimizing embryo selection with day 5 transfer

ObjectiveTo compare rates of implantation, pregnancy, miscarriage, multiple gestation, and selective reduction between patients undergoing day 5 (d5) and day 3 (d3) ETs.DesignRetrospective cohort study.SettingUniversity-based IVF center.Patient(s)The first d5 ET cycle of patients 42 years of age from 2003 to 2006 was compared with a historical control of first cycle d3 ET patients 42 years of age from 1996 to 1999 who would have met current d5 ET criteria.Intervention(s)None.Main Outcome Measure(s)Rates of implantation, clinical pregnancy, miscarriage, live birth, high order multiple pregnancy (HOMP), and selective reduction.Result(s)D5 ET patients had higher implantation rates (39% vs. 30%), with no difference in the no-transfer rate. D5 ET patients had lower rates of HOMP (2.5% vs. 11%) and HOMP delivery (0.7% vs. 3.5%), multiple pregnancy (27% vs. 33%), multiple delivery (19% vs. 26%), and twin delivery (18% vs. 23%). There were fewer selective reductions of HOMP with d5 ET (1.7% vs. 3.8%).Conclusion(s)Extended culture improves embryo selection through increased implantation, facilitating fewer embryos per transfer, which lowers multiple gestation rates and the need for HOMP reduction.