A Modified Two-Step Screening Strategy for Gestational Diabetes Mellitus Based on the 2013 WHO Criteria by Combining the Glucose Challenge Test and Clinical Risk Factors

This study determines if a modified two-step screening strategy with a glucose challenge test (GCT) 7.2 mmol/L and clinical risk factors improves the diagnostic accuracy for gestational diabetes mellitus (GDM), based on 2013 WHO criteria, while limiting the number of oral glucose tolerance tests (OGTT). This was a prospective multicentric cohort study with 1811 participants receiving both GCT and 75 g OGTT in pregnancy. Participants and health care providers were blinded for GCT. Characteristics were analyzed across four glucose tolerance groups: abnormal (7.2 mmol/L), GCT GDM (n = 165), normal GCT GDM (n = 63), abnormal GCT normal glucose tolerant (NGT) (n = 472); normal GCT NGT (n = 1113). Compared to normal GCT NGT women, normal GCT GDM women had increased rates of obesity (23.8% vs. 10.5%, p < 0.001), ethnic minority background (19.3% vs. 8.2%, p < 0.001) and a history of GDM (13.8% vs. 4.6%, p = 0.03). By combined screening of GCT 7.2 mmol/L with these risk factors, sensitivity increased to respectively, 74.1-78.1% using one risk factor, and to 82.9% using any of these risk factors with a specificity of 57.5%. By using a modified two-step screening strategy, the number of women needing both a GCT and OGTT would be reduced to 25.5%, and 52.6% of all OGTTs could be avoided, compared to a universal one-step approach.