Gestational diabetes mellitus (GDM) is any degree of glucose intolerance with onset or first recognition during pregnancy.
Hyperglycemia in pregnancy may be suggested by the presence of glycosuria, a fetus that is large for date, or polyhydramnios.
Overt diabetes mellitus may be found in women presenting with risk factors for type 2 diabetes during the first prenatal visit (before 13 weeks of gestation).