Association between gestational weight gain and risk of overweight at 3 years old: The Japan Environment and Children's Study

Background It is unclear if gestational weight gain (GWG) increases the risk of children with overweight. Objectives We examined the association between GWG and the risk of overweight in 3-year-old children in the Japanese nationwide birth cohort study. Methods Among 64 336 singleton births, we calculated the risk ratios (RRs) and 95% confidence intervals (95% CIs) of the association between GWG categories and children with overweight, following an adjustment of the confounding variables. Results GWG was positively associated with the risk of overweight among 3-year-old children. The multivariable RR (95% CI) was 1.21 (1.17-1.25) per 5 kg increase of the GWG. The multivariable RR (95% CI) for excessive GWG was 1.20 (1.12-1.28) and 1.27 (1.16-1.39) based on the modified Japanese and IOM criteria, respectively, compared to adequate GWG. The multivariable RR (95% CI) of overweight with children for inadequate versus adequate GWG was 0.83 (0.78-0.88) and 0.84 (0.79-0.89) based on the modified Japanese and IOM criteria, respectively. Conclusions GWG was positively associated with a high risk of overweight at 3 years of age. The risk of offspring overweight was 20%-27% higher and 16%-17% lower with excessive GWG and inadequate GWG, respectively, compared to adequate GWG, based on the aforementioned criteria.