Critical Windows of Fetal Lead Exposure

OBJECTIVE: Research on the role of environmental lead exposure in the complex etiology of premature birth has yielded inconsistent results. We assessed the trimester-specific effect of prenatal lead exposure on gestational age and risk of premature delivery. METHODS: We used linear and logistic regression to identify critical windows of susceptibility to lead exposure on gestational length. RESULTS: In single-trimester models, decreases in gestational length were most strongly associated with first and second trimester blood lead. In adjusted logistic regression models, a one-standard deviation increase in second trimester blood lead was associated with an odds ratio of prematurity of 1.75 (95% CI: 1.02, 3.02). CONCLUSIONS: Maternal whole blood lead levels measured during first and second trimesters yielded the most prominent inverse association with length of gestation and increased the risk of prematurity.