Objective: To determine whether increasing the number of embryos transferred beyond five increases pregnancy rates in women aged > 40 years.
Design: Retrospective analysis of cycles performed between January 1998 and July 2003.
Setting: University-affiliated teaching hospital.
Patient(s): Women aged > 40 years undergoing a fresh cycle with a day-3 ET (n = 863).
Intervention(s): None.
Main outcome measure(s): Pregnancy, chemical pregnancy, miscarriage rates, number of viable fetuses at 12 weeks' gestation, live birth rates, and number of babies delivered.
Result(s): Compared with patients with fewer than five embryos transferred, those having five or more embryos transferred had significantly increased pregnancy rates and live birth rates, more viable fetuses at 12 weeks, and significantly decreased miscarriage rates. None of these outcome variables differed between the five-embryo and more-than-five-embryo groups. There were no differences in outcome when only five embryos were transferred, regardless of whether five or more than five embryos were available. The number of embryos transferred did not significantly influence multiple birth rates.
Conclusion(s): The present study demonstrates that in women aged > 40 years, five embryos is the optimum number to transfer, and transferring more than five does not confer any additional benefit to clinical outcome.