Introduction of blastocyst culture and transfer for all patients in an in vitro fertilization program

Abstract

Objective: To evaluate the nonselective application of extended embryo culture on the outcome of IVF. Design: Retrospective analysis. Setting: Private practice assisted reproductive technology center. Patient(s): Seven hundred ninety nonselected patients undergoing IVF with controlled ovarian stimulation. Intervention(s): For day 3 ET, multicell embryos were cultured in human tubal fluid medium and 12% synthetic serum substitute. For day 5 ET, embryos were cultured for 48 hours in S1 medium and then for 48 hours in S2 medium. Main Outcome Measure(s): Implantation rate (determined by total no. of visualized gestational sacs), ongoing pregnancy rate, and number of embryos available for ET. Result(s): Respective day 3 and day 5 implantation rates for patients aged <35 years (29.5% and 38.9%), patients aged 35–39 years (20.7% and 28.2%), and all patients combined (23.3% and 32.4%) were statistically significantly different. Significantly more embryos were transferred on day 3 than on day 5 for patients aged <35 years (2.9 vs 2.4), patients aged 35–39 years (3.1 vs 2.6), and all patients combined (3.0 vs 2.5). The difference in ongoing pregnancy rates per retrieval was statistically significant for day 3 compared with day 5 transfers for all patients combined (35.9% vs 43.8%). Cancellation rates for transfer after retrieval increased significantly for day 3 compared with day 5 transfer (2.9% vs 6.7%). Conclusion(s): These results demonstrate the feasibility of using extended embryo culture in a nonselective manner for couples undergoing IVF. Overall, extended embryo culture was associated with a significant increase in pregnancy rates and implantation rates and a significant decrease in the number of embryos transferred. The rate of multiple implantation among patients aged <35 years warrants consideration of single blastocyst transfers for this group.