Evidence that birth weight is decreased by maternal lead levels below 5μg/dl in male newborns.

To assess the association between birth weight and maternal blood lead (BPb) levels, 386 pregnant women and their newborn offspring were surveyed. Mean±SD (range) maternal BPb concentrations were 0.98±0.55 (0.10-3.99), 0.92±0.63 [<0.09 (limit of quantification)-3.96], and 0.99±0.66 (<0.09-3.96)μg/dl at 12, 25 and 36 weeks' gestation, respectively. Mean±SD (range) gestational age at delivery was 38.9±1.3 (35-41) weeks. In male newborns, a significant correlation between birth weight and logBPb at 12 weeks' gestation was observed (Spearman's rank correlation coefficient=-0.145, p<0.05). Multiple regression analysis indicated that birth weight was significantly inversely associated with logBPb at 12 weeks' gestation, controlling for possible confounding variables. These results suggest that low-level exposure to lead in early gestation could be a risk factor for reduced birth weight in male offspring.