The Diabetogenic State of Maternal Metabolism in Pregnancy

Abstract

After completing this article, readers should be able to: 1. Explain why normal pregnancy has been characterized as a “diabetogenic state” and early gestation can be viewed as an anabolic condition. 2. Compare and contrast the general differences between women who have type 2 or gestational diabetes and women who have type 1 diabetes mellitus or normal glucose tolerance. 3. Describe insulin abnormalities seen in women who have gestational diabetes mellitus. 4. Characterize the relationship between neonatal birthweight and triglyceride and free fatty acid concentrations. There are significant alterations in maternal metabolism during pregnancy, which provide for adequate nutritional stores in early gestation to meet the increased maternal and fetal demands of late gestation and lactation. Although diabetes mellitus is thought of as a disorder exclusively of maternal glucose metabolism, it affects all aspects of maternal nutrient metabolism. Herein we consider maternal glucose metabolism as it relates to pancreatic beta cell production of insulin and insulin clearance, endogenous hepatic glucose production and suppression with insulin, and peripheral glucose insulin sensitivity. We also address maternal protein and lipid insulin metabolism. Lastly, we examine the impact of these alterations on maternal metabolism related to fetal growth. Normal pregnancy has been characterized as a “diabetogenic state” because of the progressive increase in postprandial glucose and insulin response in late gestation. However, early gestation can be viewed as an anabolic condition because of the increase in maternal fat stores and decrease in free fatty acid concentration. Longitudinal studies in women who have normal glucose tolerance have shown significant progressive alterations in all aspects of glucose metabolism as early as the end of the first trimester. (1) Insulin secretion progressively increases in response to an intravenous glucose challenge with advancing gestation (Fig. 1). The increases in insulin concentration are more pronounced in lean than in obese women, most …