Oocyte vitrification does not affect early developmental timings after intracytoplasmic sperm injection for women...

Oocyte vitrification causes a temporary disassembly of the metaphase plate and spindle, which needs time to recover after warming. As a consequence, early post-fertilization events-such as timing of second polar body extrusion-might be altered, with unknown effects on preimplantation development, timing to pronuclear breakdown, and timing of cleavages. The aim of this study was to evaluate if differences exist among these events when comparing embryos obtained from fresh-donated versus vitrified/warmed oocytes from young women. We performed a prospective study with 201 embryos from 100 fresh and 101 vitrified/warmed oocytes that were subsequently fertilized by intracytoplasmic sperm injection. Kaplan-Meier curves of each time period were generated, in which we observed that median developmental times did not differ between embryos from fresh versus vitrified/warmed oocytes among all the metrics assessed. Thus, for young women without fertility problems, no differences exist between the timing of early developmental milestones in embryos derived from fresh or vitrified oocytes, and vitrification does not affect the preimplantation development of the resulting embryos. Mol. Reprod. Dev. 83: 624-629, 2016. © 2016 Wiley Periodicals, Inc.