Impact of early cleaved zygote morphology on embryo development and in vitro fertilization-embryo transfer outcome: a prospective study.

摘要

OBJECTIVE: To evaluate the impact of the first division morphology on embryo development and IVF-embryo transfer outcome. DESIGN: Prospective study. SETTING: Teaching hospital, France. PATIENT(S): All zygotes from 201 couples were checked for early cleavage. We defined as "even," early cleaved (EC) zygotes with 2 cells of even size; as "uneven," EC zygotes with 2 cells of uneven size; and as fragmented, quality was assessed as "top" embryo or "non-top," with the evaluation of multinucleated blastomeres. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Day 2 embryo quality, pregnancy and implantation rates. RESULT(S): Among EC zygotes, 59.1% were even, 13.0% were uneven, and 27.9% were fragmented. Even EC yielded more "top" embryos and less multinucleated blastomere embryos than uneven EC (77.0% vs. 46.3%) and fragmented EC (77.0% vs. 13.9%). The 125 double embryo transfers that comprised at least one embryo derived from even EC zygote led to higher pregnancy rate (PR) (64.0% vs. 43.4%) and implantation rate (42.0% vs. 27.6%) compared to the 76 double embryo transfers with embryos derived from breakdown or 2PN zygotes. CONCLUSION(S): The morphology of the early cleaved zygote is involved in embryo development. Evaluation of this morphology is an effective and valuable method of assessing the embryo quality.