Day 5 blastocyst embryo transfer: time for a single embryo transfer?

Abstract

OBJECTIVE: To determine if the day of transfer (cell stage, day 5 or 6 blastocyst) affects IVF pregnancy outcome and multiple birth rates.DESIGN: Retrospective chart review.MATERIALS AND METHODS: A retrospective data review for IVF (women < 37 yo) and ovum donation cycles for the year 2006 were analyzed for embryo numbers transferred, and their grade and day of transfer, to determine live birth rates and multiple birth rates. Institutional approval for this study was obtained. Multiple regression analyses were used, and the number of embryos transferred and grade were used as covariates when multiple pregnancies were considered. Three groups were considered: cell stage transfers (transfers at 72 or 96 hours) or blastocyst transfer on day 5 or 6.Table 1Comparison of Delivered Pregnancy Rates by Day of TransferDay of TransferOdds Ratio95% CI3 vs 54.501.01 20.004 vs 59.013.05 26.326 vs 57.753.18 18.87 Open table in a new tab Table 2Comparison of Multiple Birth Rates by Day of TransferDay of TransferOdds Ratio95% CI3 vs 54.720.53 41.674 vs 53.771.12 12.666 vs 54.331.57 11.90 Open table in a new tab CONCLUSIONS: The data suggests that day 5 blastocyst transfer is superior, but yields higher multiple birth rates. A randomized trial of transferring suitable day 5 blastocysts on day 5 or 6 would clarify if the day of transfer was important. Couples seeking IVF care should seek out programs that offer day 5 blastocyst transfers and should consider a single blastocyst transfer. OBJECTIVE: To determine if the day of transfer (cell stage, day 5 or 6 blastocyst) affects IVF pregnancy outcome and multiple birth rates. DESIGN: Retrospective chart review. MATERIALS AND METHODS: A retrospective data review for IVF (women < 37 yo) and ovum donation cycles for the year 2006 were analyzed for embryo numbers transferred, and their grade and day of transfer, to determine live birth rates and multiple birth rates. Institutional approval for this study was obtained. Multiple regression analyses were used, and the number of embryos transferred and grade were used as covariates when multiple pregnancies were considered. Three groups were considered: cell stage transfers (transfers at 72 or 96 hours) or blastocyst transfer on day 5 or 6. CONCLUSIONS: The data suggests that day 5 blastocyst transfer is superior, but yields higher multiple birth rates. A randomized trial of transferring suitable day 5 blastocysts on day 5 or 6 would clarify if the day of transfer was important. Couples seeking IVF care should seek out programs that offer day 5 blastocyst transfers and should consider a single blastocyst transfer.