Non-insulin-dependent diabetes mellitus and gestational diabetes mellitus: Same disease, another name?

Non-insulin-dependent diabetes mellitus (NIDDM) effects more than 14 million Americans and is associated with significant morbidity and mortality. Gestational diabetes mellitus (GDM), which refers to glucose intolerance that has its onset or first recognition during pregnancy, has many features in common with NIDDM. First, the endocrine (impaired insulin secretion) and metabolic (insulin resistance) abnormalities that characterize both forms of diabetes are virtually identical; second, the risk factors for the development of NIDDM are similar to those for GDM; and third, the metabolic abnormalities present in normal glucose tolerant individuals at high risk of developing NIDDM, i.e., prediabetic subjects, are similar to those in subjects at risk for the development of GDM. Furthermore, women with GDM are at a markedly increased risk to develop NIDDM later in life. These observations provide a powerful argument that hgperglycemia detected for the first time in pregnancy actually represents an unveiling of preexisting metabolic abnormalities that characteristically precede the development of NIDDM. GDM thus may represent an early stage in the natural history of NIDDM. Diagnosis of GDM therefore assumes importance for two reasons. First, it will identify patients in whom aggressive glycemic control will prevent perinatal complications. Second, diagnosis of GDM also will identify patients who may benefit from early therapeutic intervention to prevent the development of NIDDM and associated complications later in life. In this article, we review in detail lines of evidence that suggest GDM and NIDDM are etiologically indistinct.