Increased neonatal fat mass, not lean body mass, is associated with maternal obesity

The purpose of this study was to compare body composition measures in neonates of women who were overweight/obese (body mass index, > or = 25 kg/m2) versus women who were lean/average (body mass index, < 25 kg/m2), all of whom had normal glucose tolerance levels.

Seventy-six neonates (34 female and 42 male) of singleton pregnancies of pregravid overweight/obese women and 144 neonates (67 female and 77 male) of lean/average women were assessed with anthropometric measures and total body electrical conductivity evaluation of body composition at birth.

There was a borderline increase in birthweight (3436 +/- 567 g vs 3284 +/- 534 g; P = .051) but not lean body mass (3020 +/- 410 g vs 2950 +/- 400 g; P = .23) in the overweight/obese versus lean/average weight groups. However, there were significant increases in percent body fat (11.6% +/- 4.7% vs 9.7 +/- 4.3%; P = .003) and fat mass (420 +/- 220 g vs 380 +/- 170 g; P = .01) in neonates of overweight/obese women versus lean/average weight women.

Overweight/obese women with normal glucose tolerance levels have neonates who are heavier than lean/average weight women because of increased adiposity. We speculate that this increased obesity in offspring of obese women with normal glucose tolerance levels is a significant risk for adolescent obesity and components of the metabolic syndrome.