Early cleavage morphology affects the quality and implantation potential of day 3 embryos

To assess the development and implantation potential of early-cleaved embryos displaying various morphological patterns. Retrospective analysis. Private IVF center. Embryos obtained from 1,556 transfer cycles were assessed. Early-cleaved embryos were grouped according to their cleavage patterns as: even (1,490); uneven (3,238); and fragmented (768), or according to nuclear morphologies as: mononucleation (2,008) and other nuclear morphologies; nonmononucleation (3,488). Seven thousand four hundred forty-five embryos were late cleaved. None. Embryo quality, pregnancy (PR), and implantation rates. Day3 embryo quality was highest in evenly early-cleaved embryos and in those displaying mononucleation. Early-cleaved embryos displaying fragmentation and late-cleaved embryos yielded the poorest day 3 quality. Early cleavage cycles displayed higher PR and implantation rate than late cleavage with the exception of other nuclear morphologies, in which similar outcome was obtained. Mononucleated early-cleaved embryos implanted at a higher frequency than early-cleaved embryos displaying other nuclear morphologies. The morphology of early cleavage correlates to day 3 embryo quality and implantation rate.