Risk-Factor Based Lead Screening and Correlation with Blood Lead Levels in Pregnancy

OBJECTIVES: Lead exposure has devastating neurologic consequences for children and may begin in utero. The American College of Obstetricians and Gynecologists recommends prenatal lead screening using a risk factor-based approach rather than universal blood testing. The clinical utility of this approach has not been studied. We evaluated a risk-factor based questionnaire to detect elevated blood lead levels in pregnancy. METHODS: We performed a secondary analysis of a cohort of parturients enrolled to evaluate the association of lead with hypertensive disorders of pregnancy. We included participants in this analysis if they had a singleton pregnancy ≥34 weeks’ gestation with blood lead levels recorded. Participants completed a lead risk factor survey modified for pregnancy. We defined elevated blood lead as ≥2 μg/dL, as this was the clinically reportable level. RESULTS: Of 102 participants enrolled in the cohort, 92 had blood lead measured as part of the study. The vast majority (78%) had 1 or more risk factor for elevated lead using the questionnaire yet none had clinical blood lead testing during routine visits. Only two participants (2.2%) had elevated blood lead levels. The questionnaire had high sensitivity but poor specificity for predicting detectable lead levels (sensitivity 100%, specificity 22%). CONCLUSIONS FOR PRACTICE: Prenatal risk-factor based lead screening appears underutilized in practice and does not adequately discriminate between those with and without elevated blood levels. Given the complexity of the risk factor-based approach and underutilization, the benefit and cost-effectiveness of universal lead testing should be further explored.