摘要Background Gestational diabetes mellitus (GDM) is a common complication during pregnancy,and gestational weight gain is one of the major and modifiable risk factors.This study aims to estimate the relationship between the rate of gestational weight gain before diagnosis of GDM and the subsequent risk of GDM.Methods A case-control study was conducted with 90 GDM cases and 165 women in the control group from May 2012 to August 2012 at Peking University First Affiliated Hospital.GDM was diagnosed according to the standards issued by the Ministry of Health of China in 2011.The plasma glucose levels,weights,and covariate data of the women were obtained based on medical records.Univariate analysis and unconditional Logistic regression model were used to estimate the associations.Results After adjusting for age at delivery,parity,and pre-pregnancy body mass index,the risk of GDM increased with increasing rates of gestational weight gain.Compared with the lower rate of gestational weight gain (less than 0.28 kg per week),a rate of weight gain of 0.28 kg per week or more was associated with increased risk of GDM (odds ratio:2.03; 95％ confidence interval:1.15 to 3.59).The association between the rate of gestational weight gain and GDM was primarily attributed to the increased weight gain in the first trimester.Conclusion High rates of gestational weight gain,particular during early pregnancy,may increase a woman's risk of GDM.