Blastocyst transfer for all? Higher cumulative live birth chance in a blastocyst-stage transfer policy compared to a cleavage-stage transfer policy

Background: In an unselected patient population, what is the cumulative live birth rate per oocyte collection cycle in a blastocyst-stage transfer policy compared to a cleavage-stage transfer policy? Methods: A retrospective cohort analysis of 1656 IVF and ICSI cycles was performed in two time-frames between January 2010 and December 2016. Transfer was scheduled, either on day 3 (n=729) or on day 5 (n=927). In this study, the main outcome measure was cumulative live birth rate per oocyte collection cycle including fresh and frozen embryo transfers in both groups. Results: The cumulative live birth rates per oocyte collection cycle were comparable between patients with cleavage-stage transfers (day 3 group) and those with blastocyst-stage transfers (day 5 group) (23.7% versus 25.5%, respectively; p = 0.42). After controlling for confounders, there was a 34% increased chance of live birth with blastocyst-stage transfer policy compared with cleavage-stage transfer policy (odds ratio (OR) =1.34; 95% confidence interval (CI), 1.051 to 1.704; p = 0.018). Conclusion: In an unselected patient cohort, the cumulative live birth chance per oocyte collection cycle is higher in a blastocyst-stage transfer policy compared to a cleavage-stage transfer policy.