Evaluation of human embryo development in in vitro fertilization- and intracytoplasmic sperm injection-fertilized oocytes: A time-lapse study

Objective: We investigated whether the insemination method (in vitro fertilization [IVF] or intracytoplasmic sperm injection [ICSI]) affected morphokinetic events and abnormal cleavage events in embryonic development.Methods: A total of 1,830 normal fertilized embryos were obtained from 272 IVF and ICSI cycles that underwent ovum retrieval culture using a time-lapse system (Embryoscope) from June 2013 to March 2015.All embryos were investigated by a detailed time-lapse analysis that measured the developmental events in the hours after IVF or ICSI insemination.Results: No significant differences were observed between the two groups regarding clinical outcomes (p > 0.05).ICSI-derived embryos showed significantly faster morphokinetics than those derived from conventional IVF, from the time to pronuclear fading to the time to 6 cells (p< 0.05).However, no significant differences were found from the time to 7 cells to the time to expanded blastocyst (p> 0.05).There were no differences in abnormal cleavage events between the two groups (p> 0.05); they showed the same rates of direct cleavage from 1 to 3 cells, 2 multinucleated cells, 2 uneven cells, and reverse cleavage.Conclusion: The morphokinetics of embryo development was found to vary between IVF-and ICSI-fertilized oocytes, at least until the 6-cell stage.However, these differences did not affect the clinical outcomes of the embryo.Additionally, no significant differences in abnormal cleavage events were found according to the fertilization method.