Morphologic Characteristic of Human Embryo Cultured in Vitro under Low Oxygen Tension.

Objective To investigate the effect of low oxygen tension ( 7.5% O₂) on human embryo development in vitro and outcome of women undergoing IVF-ET. Methods The data of 280 routine IVF cycles with fresh embryo transfer on day 3 conducted in the 2nd People's Hospital of Yunnan Province from February 2012 to August 2013 were retrospectively analyzed. Two groups, 7.5% O₂ low oxygen tension (n=120) and 20% O₂ high oxygen tension (n = 160), were setup for early embryo (D1-D3) development in vitro. Results Good quality embryo on day 3 in low oxygen tension group showed morphologically appearance of blastomere mutually clinging to each other, a characteristic of slight compaction. Higher rate of good quality embryo (66.22% V. 47.54%) and of clinical pregnancy (53.33% v. 39.22%) were found in the low oxygen tension group. There were no significantly differences in rates of fertilization, cleavage and embryo utilization respectively between the two groups (Pall >0.05) . Conclusion High quality early stage human embryos can be developed in vitro in low oxygen tension, and may improve clinic outcome of IVF. [ABSTRACT FROM AUTHOR]