Risk factors for gestational diabetes mellitus among women screened with the two-step and one-step methods: A before-and-after study

Objective: To compare the risk profiles for gestational diabetes mellitus (GDM) using a one-step and two-step screening method and diagnostic criteria. Materials and methods: A retrospective cohort study was conducted among women screened using Carpenter and Coustan's (C&C) criteria (two-step method) and the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) criteria (one-step method). All deliveries after 28 weeks of gestation, except for pregnancies complicated by pre-pregnancy diabetes mellitus, were analyzed. Multiple logistic regression was used to assess the associations between GDM and various potential risk factors. Results: Risk factors for C&C-defined GDM were pre-pregnancy body mass index >24.2 kg/m² (adjusted odds ratio [OR] 2.49, 95% confidence interval [CI] 1.92–3.23), maternal age at delivery >34 years (adjusted OR 2.46, 95% CI 1.96–3.09), history of fetal death (adjusted OR 2.56, 95% CI 1.37–4.78), and chronic hypertension (adjusted OR 3.66, 95% CI 1.50–8.91). In addition to these factors, conception assisted by reproductive technology (adjusted OR 1.64, 95% CI 1.19–2.25) and genetic amniocentesis (adjusted OR 1.19, 95% CI 1.03–1.38) were IADPSG-defined GDM risk factors. Conclusion: Risk factors for GDM differ with the diagnostic criteria used. This information is important when changing GDM screening strategies from the two-step approach to the one-step approach.