Atypical embryo phenotypes identified by time lapse microscopy High prevalence and association with embryo development

Time-lapse microscopy is used to identify and define atypical human embryo phenotypes that may aid in the deselection of poorer quality embryos, thereby improving in vitro embryo selection.


Kelly Athayde Wirka, M.S., Alice A. Chen, Ph.D., Joe Conaghan, Ph.D., Kristen Ivani, Ph.D., Marina Gvakharia, M.D., Ph.D., Barry Behr, Ph.D., Vaishali Suraj, M.S., Shehua Shen, M.D.

Volume 101, Issue 6, Pages 1637–1648.e5



To characterize atypical dynamic embryo phenotypes identified by time-lapse microscopy, evaluate their prevalence, and determine their association with embryo development.


Retrospective multicenter cohort study.


Five IVF clinics in the United States.


Sixty-seven women undergoing IVF treatment with 651 embryos.


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.


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%.


Embryos exhibiting atypical phenotypes are highly prevalent in human embryos and show significantly lower developmental potential than control embryos.

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