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.