Higher Numbers of Pregnancies Associated With an Increased Prevalence of Gestational Diabetes Mellitus: Results From the Healthy Baby Cohort Study

BACKGROUND: Pregnancy leads to substantial maternal metabolic and lifestyle alterations. However, it is still unclear whether repeated exposure to these changes will influence the development of gestational diabetes mellitus (GDM). In the present study, we aimed to investigate the association between the number of pregnancies and GDM among Chinese women. METHODS: A total of 7,008 subjects from the Healthy Baby Cohort study were included in this study. The number of pregnancies was classified into three categories: 1, 2, or ≥3 pregnancies. GDM was diagnosed using International Association of Diabetes and Pregnancy Study Groups criteria. Multivariate logistic regression models were used. RESULTS: In the fully adjusted model, women with ≥3 pregnancies had a 1.27-fold (95% confidence interval [CI], 1.05–1.54) higher risk of GDM. Among women ≥30 years old, 2 and ≥3 pregnancies were associated with a higher risk of GDM (odds ratio [OR] 1.32; 95% CI, 1.01–1.73 and OR 1.54; 95% CI, 1.17–2.01, respectively). Among women with a pre-pregnancy BMI <24 kg/m(2), ≥3 pregnancies were associated with a 1.35-fold (95% CI, 1.09–1.67) higher risk of GDM. CONCLUSIONS: Our findings suggested that higher numbers of pregnancies is an independent risk factor of GDM. The association between number of pregnancies and GDM was more prominent among women who were ≥30 years old or with a pre-pregnancy BMI <24 kg/m(2).