Elevated blood lead levels in pregnant women: identification of a high-risk population and interventions.

There has been a significant decrease in the number of preschool children with elevated blood lead levels (BLL), from 88.2 to 4.4 per 10,000 children over the last three decades as shown by National Health and Nutritional Examination Survey (NHANES) data. However, there are still certain high-risk populations that have not been well studied. One such group is that of pregnant women. During pregnancy, BLL tends to increase due to greater bone turnover, which causes release of lead stored in bone. This increase may not affect the pregnant woman's health directly but could be extremely harmful to the rapidly developing central nervous system in the fetus as it crosses the placenta easily. This current study was undertaken to estimate the prevalence of elevated BLL in pregnant women in a community hospital, monitor the effect of routine preventive practices on maternal BLL, and to elucidate the relationship between maternal and neonatal BLL and their anthropometric indices. A retrospective chart review was conducted on all hospital deliveries occurring in the first six years after the initiation of universal blood lead screening of pregnant women (n=6880). The prevalence of elevated lead (> or =10 microg/dL) in our patient population was 1.7%. The factors associated with elevated lead levels were recent immigration to the US, poor socioeconomic status and low educational levels. Simple interventions such as hand washing as well as calcium and iron supplementation significantly reduced maternal BLL from 16.82+/-9.5 to 11.48+/-9.3 microg/dL (P<0.0001). A significant correlation (r=0.4, P<0.007) is present between the post-intervention but not the pre-intervention maternal BLL and the neonatal BLL. Given the vulnerability of the developing fetal brain and that CNS complications are associated with elevated lead levels, antenatal lead screening should be part of routine prenatal care. Simple preventive measures may play a role in decreasing maternal BLL and thereby decreasing transplacental transfer of lead to the fetus.