Pregnancy outcome after blastocyst stage transfer comparing to early cleavage stage embryo transfer.

Blastocyst transfer has been introduced as an alternative for improving the chance for in vitro fertilizations (IVF) implantation. The present study was to evaluate pregnancy rates when embryo transfer was performed either on day 2-3 (cleavage stage) or on day 4-5 (blastocyst stage). This randomized clinical trial included 118 infertile women.