Metabolic disorder of pregnancy (understanding pathophysiology of diabetes and preeclampsia)

• Insulin resistance with secondary hyperinsulinemia is suspected to be the link between hypertension and diabetes.
• Gestational diabetes mellitus is characterized by inadequate β-cell secretion for the level of insulin resistance present, whether the insulin response is normal or elevated.
• The hypertensive effect of hyperinsulinemia is postulated to be due to weight gain, extracellular fluid volume expansion and increased sympathetic activity due to insulin.

The role of insulin resistance in human disease is implicated in the pathogenesis of some of the chief western chronic diseases: ischemic heart disease, type 2 diabetes mellitus, and essential hypertension. The occurrence of these diseases, alongside obesity, is termed the metabolic syndrome. Pregnancy is normally attended by progressive insulin resistance that begins near midpregnancy and progresses through the third trimester to levels that approximate the insulin resistance seen in individuals with type 2 diabetes. Insulin resistance and hyperinsulinemia may be the basic common ground for the metabolic syndrome of pregnancy – elevated blood pressure and diabetes mellitus. Moreover, the metabolic syndrome is also associated with endothelial dysfunction, oxidative stress, and attenuated inflammatory responses. In this review, we discuss the development of insulin resistance during pregnancy, hormones and newly discovered factors associated with insulin resistance and secretion, lipid metabolism, and the pathogenesis of hypertension during pregnancy.