Cleavage pattern predicts developmental potential of day 3 human embryos produced by IVF.

Time-lapse technique provides opportunities to observe the dynamic process of human early development. Previous studies have suggested several abnormal division patterns were associated with decreased developmental potential, but no systematic results are currently available. In this study, seven abnormal division patterns were observed during early cleavage, and these had different effects on the further development potential of daughter blastomeres. According to the severity and occurrence of abnormal division patterns during the initial three cleavages, an embryo hierarchical classification model was developed and day 3 embryos were classified into six grades (from A to F). The good-quality blastocyst formation rate for these grades decreased from 70.8-3.8% (P < 0.001). In a prospective observational study, 139 IVF cycles were recruited to assess the efficiency of this classification model. In the embryos that had confirmed implantation results, the implantation rate decreased from 67.0% (Grade A) to 0% (Grade D;P < 0.001). These results indicated that cleavage patterns can predict the developmental potential of day 3 human embryos.