Diagnostic Criteria and Management of Gestational Diabetes

Diagnostic Thresholds

The American Diabetes Association recommends that a fasting plasma glucose level <92 mg/dL (5.1 mmol/L) be considered normal in the first prenatal visit, while values ≥92 mg/dL but <126 mg/dL indicate early gestational diabetes that requires immediate management 1, 2
A fasting glucose level ≥126 mg/dL (7.0 mmol/L) indicates overt pre-existing diabetes, not gestational diabetes 1, 2
The International Association of Diabetes and Pregnancy Study Groups (IADPSG) consensus, based on the Hyperglycemia and Adverse Pregnancy Outcomes (HAPO) study, demonstrated continuous associations between maternal hyperglycemia and adverse outcomes, supporting the threshold of 92 mg/dL for early gestational diabetes 1, 3

The American College of Obstetricians and Gynecologists recommends that women at high risk for gestational diabetes be screened at the first prenatal visit 4
Women with a body mass index (BMI) ≥30 kg/m², previous history of gestational diabetes, first-degree relative with diabetes, previous macrosomia (>4,500 g), metabolic syndrome, or belonging to ethnic groups at high risk should be screened immediately 4
Universal screening is recommended between 24-28 weeks of gestation with a 75g oral glucose tolerance test (OGTT) for women of average risk 1, 3

A fasting glucose level <92 mg/dL is considered normal, and repeat screening is mandatory at 24-28 weeks with a 75g OGTT, even in high-risk women with an initial normal result 1, 2
A fasting glucose level ≥92 mg/dL but <126 mg/dL is diagnostic of early gestational diabetes, and immediate management with nutritional therapy and glucose monitoring should be initiated 1, 2
A fasting glucose level ≥126 mg/dL is diagnostic of overt pre-existing diabetes, requiring intensive management as pre-existing diabetes, not gestational diabetes 1, 2

The American Diabetes Association recommends the following treatment targets for women with gestational diabetes or pre-existing diabetes: fasting glucose <95 mg/dL (5.3 mmol/L), 1-hour postprandial glucose <140 mg/dL (7.8 mmol/L), 2-hour postprandial glucose <120 mg/dL (6.7 mmol/L), and HbA1c <6% (42 mmol/mol) if achieved without significant hypoglycemia 8, 9