Are We Ready for Prime Time? Prenatal Lead Screening

Background: Prenatal blood lead screening is becoming more common and has been formalized in NY for high risk mothers identified by questionnaire. However, there are no clear guidelines for the management of elevated blood lead levels (BLL) once discovered. We present two cases referred to our Poison Control Center. Case Report: Case 1: A 23 yo Mexican woman at 36 wks gestation had a BLL of 58mcg/dL. No treatment was offered. A 3kg normal female was delivered at term. The infant's BLL on day of life (DOL) 2 was 73 mcg/dL with a hemoglobin of 17 g/dL. A double volume exchange transfusion was performed on DOL 4, reducing the BLL to 11.4 mcg/dL. Additional chelation included BAL, CaNa2EDTA and oral succimer. BLL on DOL 25 was 15 mcg/dL, and the infant was referred to a high-risk development program. Case 2: A 24 yo woman at 33 weeks had a BLL of 24 mcg/dL. Subsequent levels were 35 mcg/dL at 35 weeks, and 28 at 36 weeks. Induction was recommended at this time without further treatment for the BLL. A normal female infant was delivered, BLL was 30 mcg/dL at birth. The mother received succimer chelation; the BLL one week post partum was 11 mcg/dL. The infant was not treated, and breastfeeding was discouraged; BLL on DOL 6 was 32, DOL 12 was 31. Case Discussion: Recent guidelines suggest screening all pregnant women considered high-risk for lead exposure. This involves many patients because the questionnaire identifies all foreign-born women as high risk. While there are some suggestions for intervention in these women based on BLL, there is no data or formal guideline for management such as termination, induction or chelation in these patients. These issues are complicated further by concerns of teratogenicity of chelation. Conclusion: While screening for prenatal and neonatal lead poisoning is a worthwhile goal, further study and universal guidelines are necessary to manage the mothers and newborns identified. Until these guidelines are developed, efforts should be directed at education and prevention in these high risk populations to decrease lead exposure for themselves and their newborns.