Maternal pre-pregnancy body mass index explains infant's weight and BMI at 14 months: results from a multi-ethnic birth cohort study.

OBJECTIVE To investigate the association between (self-reported) maternal pre-pregnancy body mass index (pBMI), and child's weight, height and BMI at age 14 months. DESIGN Prospective multi-ethnic community-based cohort study. SETTING Amsterdam, The Netherlands. PARTICIPANTS 8266 pregnant women from the Amsterdam Born Children and their Development study, filled out a questionnaire covering socio-demographic data, obstetric history, lifestyle, dietary habits and psychosocial factors, 2 weeks after their first antenatal visit. 7730 gave birth to a viable term singleton infant with information on birth weight, gender and pregnancy duration. Growth data were available for 3171 of these children. MAIN OUTCOME MEASURES Weight (g), height (cm) and BMI (kg/m(2)) of the child at age 14 months. RESULTS pBMI was linearly associated with weight and BMI of the child at age 14 months. One unit increase in pBMI resulted in an increment of 29 g (95% CI 19 to 39) in weight and 0.041 kg/m(2) (95% CI 0.030 to 0.053) in BMI. The effect size decreased after adjustment for birth weight (weight: beta coefficient 19 g, 95% CI 10 to 28; BMI: beta coefficient 0.034 kg/m(2), 95% CI 0.023 to 0.046) and hardly changed after adjustment for all other variables (weight: beta coefficient 21 g, 95% CI 11 to 30; BMI: beta coefficient 0.031 kg/m(2), 95% CI 0.019 to 0.043). pBMI was not related to height. CONCLUSIONS pBMI is an independent determinant of weight and BMI of the child at age 14 months. At least one third of this effect is mediated through birth weight.