Yang L, et al. - Researchers assessed if single cleavage-stage (Day 3) embryo transfer using a time-lapse (TL) hierarchical classification model achieves comparable ongoing pregnancy rates (OPR) to single blastocyst (Day 5) transfer by conventional morphological (CM) selection. For this study, eligible patients were Chinese females, aged ≤36 years, who were undergoing their first or second fresh IVF cycle using their own oocytes, and who had FSH levels ≤12 IU/mL on Day 3 of the cycle and 10 or more oocytes retrieved. Outcomes revealed significantly lower OPR in correlation with day 3 single embryo transfer (SET) with a hierarchical classification model compared with Day 5 SET with CM selection.