Is Prenatal Lead Exposure a Concern in Infancy? What Is the Evidence?

Abstract

Exposure to unhealthy and unsafe environments cause 1 in 4 deaths in childhood each year. Early exposure to lead beginning prenatally and continuing throughout childhood is one of the mechanisms associated with unhealthy and unsafe environments, particularly in industrial countries and urban communities. Lead is a known heavy metal that crosses the placenta and blood-brain barrier depositing in fetal tissues. The purpose of this integrative review was to determine which maternal-fetal dyads were at high risk for elevated umbilical cord lead (Pb) levels and to examine the consequences associated with elevated umbilical cord Pb levels. PubMed was searched to obtain English language publications from 2005 to March 2015 for studies examining the effects of prenatal lead exposure on infant outcomes using key terms "lead" combined with "infant." A total of 17 articles were retained for analysis. Infants with elevated umbilical cord blood lead levels were associated with maternal demographic factors and country of origin. Maternal-specific exposure to lead products prior to or during pregnancy was associated with elevated umbilical cord blood lead levels. The consequences of prenatal lead exposure to the infant at birth anthropometrically were mixed. The evidence on neurological consequences of prenatal exposure to lead appears to reflect changes in cognitive impairment; however, it needs further study. The major recommendation is primary prevention of lead exposure across the life span. Implementation of policies that reduce the availability of leaded products to reduce leaded products, especially ones aimed at children and women of childbearing age. Research needs to be focused in 2 directions: (1) prevention of lead exposure during pregnancy and (2) prevention of lead leaching from bones for all women of childbearing age.