Greater neonatal fat-free mass and similar fat mass following a randomized trial to control excess gestational weight gain

OBJECTIVE: To determine the effectiveness of controlling maternal gestational weight gain in the second and third trimesters on neonate body composition. METHODS: 210 healthy women with overweight (BMI ≥ 25 < 30) or obesity (BMI ≥30 kg/m(2)) randomized to a lifestyle intervention (LI) program focused on controlling gestational weight gain through nutrition and activity behaviors or to usual obstetrical care (UC). Infant fat and fat-free mass at birth were measured by air displacement plethysmography (PEAPOD) and by quantitative magnetic resonance (QMR). RESULTS: At baseline, there were no between group differences in maternal characteristics (mean (±SD)): age 33.8 (±4.3) years, weight 81.9 (±13.7) kg, BMI 30.4 (±4.5) kg/m(2), gestational age at randomization 14.9 (±0.8) wk. GWG was less in the LI group by 1.79 kg (p=0.003) or 0.0501 kg/wk (p=0.002). Compared to UC, LI infants had greater weight (131±59 g p=0.03), fat-free mass (98±45 g; p=0.03) by PEAPOD, and lean mass (105±38 g; p=0.006) by QMR. Fat mass and percentage fat were not significantly different. CONCLUSION: Intervening in women with overweight and obesity through behaviors promoting healthy diet and physical activity to control gestational weight gain resulted in neonates with similar fat and greater fat-free mass.