Association between blood lead level during pregnancy and birth weight: A meta-analysis.

BACKGROUND We aimed to provide a quantitative summary of evidence for a relationship between prenatal lead (Pb) exposure and birth weight. METHODS PubMed and Web of Science databases were searched for eligible epidemiological studies. We transformed findings in eligible studies with different effect-size metrics to standardized regression coefficients, and used fixed-effects or random-effects models to assess the pooled effects of prenatal Pb exposure on birth weight. RESULTS There was a significant negative association between prenatal Pb exposure and birth weight. Birth weight reduction was associated with elevated lead levels in maternal blood (β = -0.094; 95% confidence interval [CI]: -0.157 to -0.030) and cord blood (β = -0.120; 95% CI: -0.239 to -0.001). CONCLUSIONS This meta-analysis is the first to provide a quantitative assessment of Pb exposure during pregnancy and an increased risk of lower birth weight.