Causes of intrauterine growth restriction and the postnatal development of the metabolic syndrome.

The term intrauterine growth restriction (IUGR) is assigned to newborns with a birth weight and/or birth length below the 10th percentile for their gestational age and whose abdominal circumference is below the 2.5th percentile with pathologic restriction of fetal growth. IUGR is usually due to maternal, fetal, or placental factors. However, many IUGR cases have unknown underlying cause. Recent studies focus on new factors that can influence fetal development and birth outcome like the timing and the type of fetal nutrition, maternal psychosocial stress and personality variables, 11beta-hydroxysteroid dehydrogenase type 2 placental activity, the activity of the neuroendocrine system that mediates the effects of psychosocial stress, and the role of proinflammatory cytokines and of oxidative stress. Data have shown that IUGR is associated with a late life increased prevalence of metabolic syndrome, a condition associating obesity with hypertension, type 2 diabetes mellitus (DM2), and cardiovascular disease. Recent data demonstrated that the diabetes-associated mortality appears to be disproportionately concentrated among individuals of abnormal birth weight.