Direct Unequal Cleavages: Embryo Developmental Competence, Genetic Constitution and Clinical Outcome

ObjectiveTo investigate the prevalence, developmental potential, chromosomal constitution and clinical outcome of embryos with direct unequal cleavages (DUC).DesignA retrospective observational study.SettingAcademic Institution.Participant21,261 embryos from 3,155 cycles cultured in EmbryoScope®.ResultsThe total incidence of DUCs per embryo occupying the first three cleavages were 26.1%. Depending of the cell stage, DUC rate was 9.8% at first cleavage (DUC-1), 9.1% at second cleavage (DUC-2), and 3.7% at third cleavage (DUC-3) with 3.6% of embryos exhibiting multiple DUCs (DUC-Plus). The occurrence of DUCs was not correlated with female gamete age or source. The incidence of DUC-1 was significantly higher in embryos fertilized by epididymal and testicular sperm (13.6% and 11.4%, respectively) compared to ejaculated sperm (9.1%, all pConclusionBlastocyst formation, implantation potential and euploid rate were significantly reduced in DUC embryos. DUC embryos should be deselected for D3 transfers, but should be culture to blastocyst stage for possible ET.