Risk Factors for Gestational Diabetes Mellitus (GDM) in Subsequent Pregnancy Among Women Without GDM History in China: A Multicenter Retrospective Study

ObjectiveThis study aimed to determine the likelihood of gestational diabetes mellitus (GDM) in subsequent pregnancy among women without GDM history and to identify risk factors for GDM in subsequent pregnancy.MethodsThis retrospective cohort study involved participants who delivered twice in same hospital of 18 research centers when delivered the second baby from January 2018 to December 2018. Finally 6204 women were enrolled and 5180 women without GDM history were analyzed further. Women were categorized as non-GDM or GDM based on the blood glucose values of the subsequent pregnancy, and the characteristics and GDM risk of these groups were compared. A univariate analysis of potential risk factors was performed using the Chi-squared test and/or t-test for qualitative or quantitative variables, respectively. Associations with P values ResultsIn primary analysis of 6204 women, the incidence of GDM in subsequent pregnancy is 48.9% (490/1002) in women with GDM history and 16.1% (835/5202) in women without GDM history. In a further analysis for 5180 women without GDM at index pregnancy, compared with the non-GDM group, the GDM group had a significantly higher age, prepregnancy body mass index, and blood glucose value at each oral glucose tolerance test (OGTT) timepoint (fasting, 1 h and 2 h) during the index and subsequent pregnancies, as well as higher weight retention during the interval between the two pregnancies (P<0.001). Age above 35 years in subsequent pregnancy (odds ratio (OR)=1.540, 95% confidence interval (CI) = 1.257-1.886, P<0.001), macrosomia in index pregnancy (OR=1.749, 95% CI=1.277-2.395, P=0.001), OGTT blood glucose values in index pregnancy (fasting, OR=2.487, 95% CI=1.883-3.285, P<0.001; 1 h, OR=1.142, 95% CI=1.051-1.241, P=0.002; 2 h, OR=1.290, 95% CI=1.162-1.432, P<0.001) and weight retention (OR=1.052, 95% CI=1.035-1.068, P<0.001) were independent risk factors for GDM in subsequent pregnancy.ConclusionFor women without GDM history, GDM risk factors including age, macrosomia history, OGTT value, and weight retention, these can be evaluated before a subsequent pregnancy. Early warning and interventions are needed for women at high risk.