Single blastocyst transfer: a prospective randomized trial

Objective: To determine the efficacy of single blastocyst transfer. Design: Prospective randomized trial. Setting: Private assisted reproductive technology unit. Patient(s): Forty-eight women undergoing IVF-embryo transfer with day 3 FSH less than or equal to 10 mIU/mL and at least 10 follicles >12 mm in diameter on day of hCG administration. Intervention(s): Embryo culture to the blastocyst stage in sequential media G1/G2 followed by transfer of either one or two blastocysts. Main Outcome Measure(s): Implantation rate, ongoing pregnancy rate, and twinning. Result(s): The transfer of a single blastocyst resulted in an implantation and ongoing pregnancy rate of 60.9% with no twins. The transfer of two blastocysts resulted in an implantation rate of 56%, an ongoing pregnancy rate of 76% with a 47.4% incidence of twins. Conclusion(s): Single blastocyst transfer is an effective method of eliminating multiple births while maintaining high pregnancy rates in this selected group of patients.