Effect of prenatal lifestyle intervention on maternal postpartum weight retention and child body mass index z-score at 36 months

BACKGROUND/OBJECTIVES: We previously reported results from a randomized trial showing that a behavioral intervention during pregnancy reduced excess gestational weight gain but did not impact maternal weight at 12 months. We now examine the longer-term effects of this prenatal intervention on maternal postpartum weight retention and toddler body-mass-index z scores (BMIz) over 36 months. SUBJECTS/METHODS: Pregnant women (N = 264; 13.7 weeks’ gestation; 41.6% Hispanic) with overweight or obesity were randomized into usual care or prenatal intervention. Anthropometric assessments in mothers and toddlers occurred at baseline, 35 weeks’ gestation and after delivery at 6, 12, 18, 24, and 36 months. RESULTS: At 36 months, prenatal intervention vs. usual care had no significant effect on the proportion of participants who returned to their early pregnancy weight or below (33.3% vs. 39.5%; p = 0.12) and had no effect on the magnitude of weight retained (2.8 [0.8, 4.8] vs 3.0 kg [1.0, 4.9], respectively; mean difference = 0.14 [−3.0, 2.7]). There was also no statistically significant intervention vs. usual care effect on infant BMIz or skinfold changes over time; toddler BMIz increased by 1.4 [−1.7, 1.0] units in the intervention group and 1.6 [−1.2, 1.8] units in the usual care group from delivery to 36 months (difference = 0.16 [−0.32. 0.63]). The proportion of toddlers at risk for obesity at 36 months was similar in intervention and usual care groups (28/77 [36.4%] vs 30/80 [37.5%]; p = 0.77). CONCLUSIONS: Compared with usual care, lifestyle intervention during pregnancy resulted in similar maternal and toddler anthropometric outcomes at 36-months postpartum in a diverse US sample of women with overweight and obesity. To sustain improved maternal weight management initiated during pregnancy, continued intervention during the postpartum years may be needed.