Critical windows of fetal lead exposure: adverse impacts on length of gestation and risk of premature delivery.

Abstract

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. We used linear and logistic regression to identify critical windows of susceptibility to lead exposure on gestational length. 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). 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.