Intrauterine growth and postnatal fasting metabolism in infants of obese mothers.

We compared neonatal fasting metabolism in 12 infants of obese women and 10 control infants born to lean mothers. Weight gain during pregnancy was less among obese women (7.2 vs 13.6 kg). Term infants born to obese women were heavier (3.9 bs 3.2 kg), had greater triceps and midscapular skinfold thicknesses, and had heavier placentae (687 vs 572 gm). Length and head circumference were not affected. After birth, fasting blood glucose concentrations declined in obese infants to hypoglycemic levels at 60 minutes of the study (26.3 vs 63.1 mg/dl). Insulin levels were not statistically different between the two groups. The postnatal rise of free fatty acids and glycerol was augmented in infants of obese mothers, whereas the decline of plasma beta-hydroxybutyrate values was augmented in infants of obese mothers, whereas the decline of plasma beta-hydroxybutyrate values was attenuated. Cord vein and artery plasma triglyceride concentrations were elevated in infants of obese mothers, and the usual rise of triglycerides with fasting after birth was further augmented in these infants. These data suggest that despite less than optimal maternal weight gain, sufficient or even surplus fuels are provided to the fetus of the obese mother and results in augmented fetal growth. Furthermore, the occurrence of fasting hypoglycemia necessitates careful monitoring of postnatal blood glucose values.