Guideline source: Centers for Disease Control and Prevention
Published source: Morbidity and Mortality Weekly Report, April 27, 2007
Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5616a4.htm
Evidence on the adverse health effects of moderate- and low-level blood lead concentrations is mounting. Public health authorities use higher levels to define blood lead levels of concern in nonpregnant women (≥ 25 μg per dL [1.20 μmol per L]) than in pregnant women (≥ 5 μg per dL [0.25 μmol per L]), in whom maternal and fetal levels are nearly identical because lead crosses the placenta unencumbered. The difference in blood lead levels for nonpregnant and pregnant women has received attention because of the recognition that a proportion of nonpregnant women with blood lead levels greater than 5 μg per dL may become pregnant and potentially expose their infants to the adverse health effects from lead. The Centers for Disease Control and Prevention (CDC) summarized 2004 surveillance data on elevated blood lead levels among women of childbearing age (i.e., 16 to 44 years) in 37 states participating in the CDC's Adult Blood Lead Epidemiology and Surveillance (ABLES) program, and emphasized the need for necessary surveillance measures to prevent lead exposure in women of childbearing age.
Adverse health effects in infants born to women with moderately elevated blood lead levels (i.e., 10 to 15 μg per dL [0.50 to 0.70 μmol per L]) include preterm birth, decreased gestational maturity, lower birth weight, reduced postnatal growth, increased incidence of minor congenital anomalies, and early neurologic or neurobehavioral deficits. Some evidence documents associations between prenatal elevated blood lead levels and decreased intelligence when those children are three to seven years of age. Estimates have varied widely concerning the number and rate of women of childbearing age with elevated blood lead levels; however, conducting surveillance of elevated blood lead levels in this population is important because approximately one third to one half of U.S. pregnancies are unplanned. Primary and secondary prevention of lead exposure among women of childbearing age, which includes identifying and counseling women who might become pregnant and expose their infant to lead in utero, is needed to lessen the risk of possible neurobehavioral and cognitive defects in their children.
Rates of elevated blood lead levels detected in the ABLES program among women who worked in the manufacturing sector, especially in the industry that includes battery manufacturing, were much higher than those of the general population for all lead exposures. These increased rates suggest that the workplace remains a substantial source of lead exposure, and physicians should consider work history when determining whether to measure blood lead levels.