Trimester-specific prenatal heavy metal exposures and sex-specific postpartum size and growth

BACKGROUND. There has been limited research considering the effects of prenatal exposure to multiple heavy metals on early childhood size and growth. OBJECTIVE. We evaluated prenatal exposures to 15 heavy metals in association with measures of weight, length, and head circumference (HC) measured at birth, and one, three and six months of age in a study of 358 mother-child pairs. METHODS. Urinary concentrations were measured in the first and third trimesters of pregnancy and examined, using sex-stratified general linear models, in association with average standardized size and changes in size (growth) over the first six months of life. Confounding effects among metals were explored. RESULTS. Increased first trimester Hg and V were associated with decreased average HC among males and weight among females, respectively. Increased first trimester V was associated with a decline in weight among females over time. Increased third trimester Cs, Rb and Tl were associated with increased average weight and HC among males. Increased third trimester Se was associated with increased HC among females over time. Evidence for confounding was observed between Cs, Rb and Tl in association with weight and HC. SIGNIFICANCE. We observed multiple biologically plausible associations between prenatal heavy metal exposures and postnatal size and growth.