Postnatal growth outcomes and influence of maternal gestational weight gain: a prospective cohort study in rural Vietnam

BACKGROUND Suboptimal weight gain during pregnancy may result in adverse outcomes for both the mother and child, including increased risk of pre-eclampsia and gestational diabetes, delivery of low birth weight and small-for-gestational age (SGA) infants, and preterm delivery. The objectives of this study were to identify maternal predictors of rate of weight gain in pregnancy, and to evaluate the association of gestational weight gain with infant postnatal growth outcomes. METHODS We conducted a prospective cohort study of infants born to women who had previously participated in a double-blind cluster randomized controlled trial of antenatal micronutrient supplementation, in Ha Nam province, Vietnam. Pregnant women (n = 1258) were seen at enrolment and 32 weeks gestation, and infants (n = 965) were followed until 6 months of age. Primary outcome was infant anthropometric indicators at 6 months of age (weight for age, length for age, weight for height z scores), and infant weight gain velocity during the first 6 months of life. RESULTS Low body mass index (<18.5 kg/m2) was present in 26% of women, and rate of gestational weight gain was 0.4 kg per week [SD 0.12]. Rate of weight gain during pregnancy was significantly associated with infant weight-for-age (MD 1.13, 95% CI 0.58 to 1.68), length-for-age (MD 1.11, 95% CI 0.66 to 1.55), weight-for-length z scores (MD 0.63, 95% CI 0.07 to 1.19), and infant weight gain velocity during the first 6 months of life (MD 93.6 g per month, 95% CI 8.2 to 179.0). CONCLUSIONS Rate of gestational weight gain is predictive of postnatal growth at six months of age in this setting. Public health programs should be targeted towards improving body mass index and weight gain in pregnant women in rural Vietnam.