Maternal obesity and body composition of the neonate.

Obese women generally deliver heavier infants, but the body composition of these infants is unknown. The principal objective of this study was to determine if neonates of obese women have more adipose tissue. At 35-36 weeks of gestation, a fasting blood sample was collected from 37 pregnant women. Shortly after birth, the body fat of the neonates was measured with an infant total-body electrical conductivity (TOBEC) instrument using a prediction equation derived from 10 miniature pigs. At 6 weeks post partum, the infant body fat was measured a second time, and the body fat of each mother was measured using an adult TOBEC instrument. We found no differences between the obese (n = 16) and lean subjects (n = 21) in the concentrations of glycerol, beta-hydroxybutyrate, triglyceride, total cholesterol, high-density lipoprotein cholesterol, or glucose in the blood. However, the insulin concentration was elevated in the obese women (199 +/- 57 pmol/l) as compared with the lean women (128 +/- 68 pmol/l, p < 0.01). At birth, maternal adiposity (% body fat) was significantly associated with infant adiposity (r = 0.37, p < 0.05). However, by 6 weeks post partum the association no longer existed. Multiple regression analysis showed that maternal adiposity, fasting glucose level, and gestational age are independently associated at birth with infant adiposity.