Yang L, et al. - In this work, researchers investigated if single cleavage-stage (Day 3) embryo transfer using a time-lapse (TL) hierarchical classification model would achieve comparable ongoing pregnancy rates (OPR) to single blastocyst (Day 5) transfer by conventional morphological (CM) selection. They noted that the OPR from Day 3 cleavage-stage single embryo transfer (SET) using hierarchical classification time-lapse selection was markedly lower compared with that from Day 5 blastocyst SET using conventional morphology, however, in women undergoing IVF, it seemed to be clinically acceptable.