Gestational Hyperglycemia, Excessive Pregnancy Weight Gain and Risk of Fetal Overgrowth

Abstract

Between 1989 and 2004 the prevalence of gestational diabetes mellitus (GDM) in the US increased from 1.9% to 4.2% in parallel with the well documented obesity epidemic (Getahun et al., 2008; Mokdad et al., 2001). However, an additional 9-20% of pregnant women, with a milder form of glucose intolerance which does not meet the diagnostic criteria for GDM, may also be at risk of type 2 diabetes, cardiovascular disease and problems while pregnant (Stamilio et al., 2004; Mello et al., 1997; Bo et al., 2004; Nordin et al., 2006). Fetal overgrowth, defined as macrosomia (birth weight >4000g) or large-for-gestational-age birth (LGA, birth weight >90th percentile for a given gestational age) increases maternal morbidity from operative delivery and also causes serious consequences to the offspring including birth trauma, obesity during childhood and type 2 diabetes and metabolic syndrome in adult life (Boney et al., 2005; Zhang & Bowes, 1995; Langer, 2000). GDM and excessive pregnancy weight gain, especially in obese women are known risk factors for fetal overgrowth (Ray et al., 2001; Hillier et al., 2008). Although previous research has suggested that metabolic abnormalities are also present in pregnant women with less severe hyperglycemia, the clinical implications of milder maternal hyperglycemia are poorly described (Chen et al., 2010; Cheng et al., 2006; Nordin et al., 2006). The primary objective of this chapter is to use prospective data from a population of low income and minority women to examine (i) the influence of maternal hyperglycemia including GDM and less severe maternal hyperglycemia on risk of fetal overgrowth; (ii) the association of longitudinally measured excessive pregnancy weight gain with risk of fetal overgrowth (IOM, 2009); (iii) the independent contribution of gestational hyperglycemia and excessive pregnancy weight gain to fetal overgrowth. Because gestational hyperglycemia and excess weight gain during pregnancy are preventable risk factors, early detection and treatment of mild hyperglycemia and monitoring pregnancy weight gain may be important for reducing the risk of LGA, for reducing childhood and later obesity and for improving the long term risk for metabolic disease.