Maternal weigh gain during pregnancy and overweight in Portuguese children

Objective: The objective of our study was to assess the association between maternal weight gain during pregnancy and childhood overweight. Design: This study was a cross-sectional analysis. Setting: The data were derived from a community-based survey of children from primary schools of Portugal. Subjects: The study was performed in a sample of 6-12-year-old Portuguese school children (2445 girls and 2400 boys; age was 8.5 +/- 0.91 years). Measurements: Height and weight were measured according to international standards, and body mass index (BMI) was calculated. The definition of overweight was based on average centiles according to the International Obesity Task Force cutoffs. Children's parents completed a self-administered questionnaire, which provided information on general family background characteristics, maternal weight gain during pregnancy and children's physical activity. The response rate was 70.6%. Children's dietary intake was measured using a 24-h dietary recall. Logistic regression models were fitted to estimate the magnitude of the association between maternal weight gain during pregnancy and overweight in their children, adjusting for confounders (gender, age, birthweight, order of birth, breastfeeding, smoking during pregnancy, physical activity, parental BMI, parental education, calcium to protein ratio and energy intake). Results: The prevalence of overweight (including obesity) was 29% in boys and 33% in girls. The odds favouring overweight (including obesity) increased significantly for those women who gained >= 16 kg during pregnancy, compared to those with < 9 kg, even after adjustment for confounders (crude odds ratio (OR) 1.53, confidence interval (CI) 95% 1.27-1.84, P-trend < 0.001; Adjusted OR=1.27, CI 95% 1.01-1.61, P-trend = 0.038). Conclusion: Large maternal weight gain during pregnancy (>= 16 kg) was significantly associated with higher risk of overweight in Portuguese children.