Objective To analyze the risk factors of gestational diabetes mellitus（GDM） using multicenter clinical data and explore its influence on pregnancy outcome. Methods A total of 5 038 cases of pregnant women from February 2012 to March 2019 in 3 obstetric hospitals in Chongqing were selected

according to the diagnostic criteria for diabetes screening for GDM

to analyze the risk factors of GDM and compare the difference of pregnancy outcome between GDM group and non GDM group. Results The differences between GDM group and non-GDM group in age

body mass index before pregnancy

weight gain during pregnancy

parity

number of pregnancies and previous cesarean section history were statistically significant（P<0.05）. Logistic regression analysis showed that age≥35 years old

overweight and obesity before pregnancy

low weight gain during pregnancy

2～4 times and ≥5 times of pregnancy

and previous cesarean section history were risk factors for GDM. The incidence of hypertensive disorder complicating pregnancy

edema

premature rupture of membranes

premature delivery

cesarean section and macrosomia in GDM group were significantly higher than those in non-GDM group（P<0.05）. Conclusion Age≥35 years old

overweight and obesity before pregnancy

too little weight gain during pregnancy are all risk factors for GDM

and the incidence of adverse pregnancy outcomes for GDM pregnant women is relatively high. Therefore

for GDM pregnant women

early blood glucose screening

regular prenatal examination and effective control of blood glucose level

and early prevention and control of high-risk factors are necessary to obtain good maternal and infant outcomes.