Atypical embryo phenotypes identified by time-lapse microscopy: high prevalence and association with embryo development

ObjectiveTo characterize atypical dynamic embryo phenotypes identified by time-lapse microscopy, evaluate their prevalence, and determine their association with embryo development.DesignRetrospective multicenter cohort study.SettingFive IVF clinics in the United States.Patient(s)Sixty-seven women undergoing IVF treatment with 651 embryos.Intervention(s)Embryo videos were retrospectively analyzed for atypical phenotypes.Main Outcome Measure(s)Identification of four groups of atypical embryo phenotypes: abnormal syngamy (AS), abnormal first cytokinesis (A1cyt), abnormal cleavage (AC), and chaotic cleavage (CC). Prevalence and association with embryo morphology and development potential were evaluated.Result(s)A high prevalence of atypical phenotypes was observed among embryos: AS 25.1% (163/649), A1cyt 31.0% (195/639), AC 18% (115/639) and CC 15% (96/639). A high percentage of embryos with atypical phenotype(s) had good quality on day 3 (overall grade good or fair): AS 78.6% (70/89); A1cyt 79.7% (94/119), AC 86.4% (70/81), and CC 35.2% (19/54), but the blastocyst formation rates for these embryos were significantly lower compared with their respective control groups: AS 21.5% vs. 44.9%, A1cyt 21.7% vs. 44.6%, AC 11.7% vs. 43.1%, and CC 14.0% vs. 42.3%.Conclusion(s)Embryos exhibiting atypical phenotypes are highly prevalent in human embryos and show significantly lower developmental potential than control embryos.Clinical Trial Registration NumberNCT01369446.