Objective:This study aims to explore the influencing factors of multiple pregnancies following assisted reproductive technology. Methods:The study included 19 434 embryo transferred cycles(14 765 singleton pregnancy cycles,4 669 multiple pregnancy cycles)resulted in clinical pregnancy from four reproductive centers in China(the First Affiliated Hospital of Nanjing Medical University,the Obstetrics and gynecology Hospital Affiliated to Nanjing Medical University,the Third Affiliated Hospital of Zhengzhou University,and the Shengjing Hospital of China Medical University),during January 2013 and December 2016. Logistic regression model was used to analyze the related factors of the occurrence of multiple pregnancies. Result:In multivariable logistic regression analysis,transplanting two embryos was the major factor in multiple pregnancies,and the odds ratio(OR)compared with single embryo transfer was 36.54,95% confidence interval(CI):27.89~47.86. Age,cycle type,progesterone level on hCG trigger day,number of oocytes retrieved,stage of embryo transferred and cumulative embryo score were associated with multiple pregnancies from double embryo transfer[OR(95% CI)were:0.62(0.55~0.70),0.84(0.77~0.92),0.86(0.80~0.92),1.21(1.12~1.31),1.28(1.13~1.46),1.19(1.15~1.23),respectively]. High cumulative embryo score was the only factor associated with decreased risk of multiple pregnancies from single embryo transfer(OR:0.68;95% CI:0.47~0.99). Conclusion:Number of embryos transferred,age,cycle type,progesterone level on hCG trigger day,number of oocytes retrieved,stage of embryo transferred and cumulative embryo score were identified as related factors of multiple pregnancies following assisted reproductive technology.