Gestational Diabetes Mellitus (GDM) Diagnosis

Two-step approach (ACOG): 1-hour 50g GCT ≥140 mg/dL is positive screen; 3-hour 100g OGTT diagnoses GDM if ≥2 values exceed: fasting ≥95, 1hr ≥180, 2hr ≥155, 3hr ≥140 mg/dL. One-step approach (ADA): 75g OGTT diagnoses GDM if any value exceeds fasting ≥92, 1hr ≥180, or 2hr ≥153 mg/dL.