Abstract: Factors affecting human blastocyst formation in vitro LUZhenYu ZHANG Yun Shan Miruoran Tianjin Central Hospital of Gynecology & Obsterics, Tianjin 300052, China Abstract Objective: To investigate the factors affecting human blastocyst formation in vitro. Methods: Through sequential culturing the D3 discarded embryos to D5-7, we observed the blastocyst formation and detect the relationship between the D3 embryo cells number, quality grade and the blastosysts quality, the formation of the high-quality blastocysts, providing the academic basis for the blastocyst transplantation. 406 D3 discarded embryos entered this experiment. Cultured these embryos with CCM, observed theirs changes daily till D5-7. Results: 102 blastocysts were formed including 28 high-quality blastocysts using the blastocyst grade standard from Gardener. The blastulation rate was 25.12%. Among 64 patients who have blastocysts, 32 patients pregnancied, the pregnancy rate is higher than whose without blastocysts (50%Vs28.79%, P<0.05). Conclusion: The blastultions rate is positively correlative with the D3 embryo cells numbers. The blastulation rate of the embryos withⅠ-Ⅱ+ degree is high than those with Ⅲ-Ⅳ degree.

Key words: embryo, blastocyst, pregnancy rate