Optimizing embryo selection with day 5 transfer.

OBJECTIVE

To compare rates of implantation, pregnancy, miscarriage, multiple gestation, and selective reduction between patients undergoing day 5 (d5) and day 3 (d3) ETs.

DESIGN

Retrospective cohort study.

SETTING

University-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.