Superfund Research Program

Lead Mobilization During Pregnancy and Lactation in Urban Women

Project Leader: Jacqueline M. Moline
Grant Number: P42ES007384
Funding Period: 1995 - 2001

Project-Specific Links

Final Progress Reports

Year:   1999 

Researchers are exploring whether lead is mobilized from stores in women's bones during pregnancy and lactation. They hypothesize that lead is mobilized during pregnancy and lactation along with calcium, phosphorus and other bone minerals. There is concern that if lead is mobilized during childbearing, it can pose a serious risk to the fetus and newborn infant because lead easily crosses the placenta and also concentrates in breast milk.

Project investigators are utilizing an X-Ray Fluorescence (XRF) technique (using K shell x-rays fluoresced by 109-Cd) for direct, non-invasive measurement of bone lead stores. This technique is being used to determine whether the metabolic stress of pregnancy and lactation can cause mobilization of stored skeletal lead. The researchers are also investigating whether deficiency of maternal iron stores enhances mobilization of lead. Data from this study will provide a basis for the development of scientifically based recommendations for the prevention of lead poisoning in urban children and women.

A total of 283 women were enrolled in the study. Seventy women who completed the baseline questionnaire became pregnant. Thirty-five women completed their pregnancies; 22 women completed the first postpartum examination (six weeks), and 13 women also completed the second postpartum examination (six months).

Lead levels in both blood and bone were low-much lower than anticipated--in this group of urban, predominantly minority women. There was no statistically significant difference in bone and blood lead levels between African-American, Hispanic and Caucasian women. Similarly, there was no significant change in bone lead levels before and after pregnancy. Too few women in the study breast-fed their children to be able to detect changes in body burden of lead brought about by lactation.

These data do not support the hypothesis that there is clinically significant cortical bone lead mobilization during pregnancy in women with low baseline body burdens of lead. Dietary data collected are currently being analyzed to determine whether body burdens of lead are influenced by dietary intake.