Unresolved controversies in gestational diabetes: implications on maternal and infant health

Gestational diabetes mellitus (GDM) is a major public health concern because of rising rates and offspring consequences; yet, expert panels are in complete disagreement on how to diagnose and optimally treat GDM. This review underscores why there remains no diagnostic standard, no agreement on whether excess dietary carbohydrate or fat should be reduced, and whether oral hypoglycemic therapy is safe given the unknown offspring effects on hepatic, pancreatic, or fat development.

New diagnostic criteria proposed by the American Diabetes Association would triple the prevalence of GDM (∼18%). Whether the treatment of women with these milder degrees of hyperglycemia will improve pregnancy outcomes is unknown given the powerful effect of obesity alone on excess fetal growth. There are data that restricting carbohydrate in the diet by substituting fat to blunt postprandial glucose levels may worsen maternal insulin resistance and that metformin may increase offspring subcutaneous fat.

The adoption of the new American Diabetes Association diagnostic criteria for GDM was rejected by ACOG and not endorsed by the NIH. Yet, varying criteria are used by different centers resulting in confusion for both patient care and research. Both maternal diet and agents that cross the placenta could potentially modify offspring gene expression. Better identification and treatment of mothers and fetuses at risk may have far-reaching implications for maternal and child health.