Risk-Factor Based Lead Screening and Correlation With Blood and Bone Lead Levels in Pregnancy [27K

Abstract

INTRODUCTION: 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 the association of bone and blood lead with a prenatal risk assessment questionnaire. METHODS: We enrolled a convenience sample of parturients ≥34 weeks’ gestation, with a singleton pregnancy, who were admitted from the obstetrical triage unit. We measured blood lead before delivery and bone lead ≤4 days postpartum using a portable X-ray spectrometer. We defined detectable blood lead as ≥2 ug/dL and detectable bone lead as ≥10 ug/g. The IRB approved the study. RESULTS: We enrolled 102 participants, of whom 100 had lead measured. We identified ≥1 risk factor among 78% of participants; none had clinical blood lead testing. The median blood lead was 0.2 ug/dL (0.2–0.4) and median bone lead was 3.8 ug/g (2.0–6.6). Blood lead, but not bone lead, was significantly higher for parturients born outside the US (P=.01). Two participants (2.2%) had detectable blood lead, while 16 (16.2%) had detectable bone lead. The questionnaire had good sensitivity but poor specificity when using blood (sensitivity 100%, specificity 22%), and bone (sensitivity 94%, specificity 25%) as the gold standard for lead exposure. CONCLUSION: This study showed that a risk-based approach for detecting lead exposure identifies parturients with high lead levels, but this approach was infrequently used clinically and has poor specificity.