Relationship among placental cadmium, lead, zinc, and copper levels in smoking pregnant women.

Previous studies on Cd-exposed pregnant animals have reported a Cd-Zn interaction that result in increased placental Cd levels and decreased placental Zn transport. In this study, placental Cd, Pb, Cu, and Zn status in pregnant women exposed to Cd and Pb through cigarette smoke was investigated. Placental tissues obtained from 30 nonsmokers (controls), 70 passive smokers, and 90 smokers were analyzed for Cu and Zn levels using an atomic absorption spectrophotometer and for Pb and Cd levels using an EG&G PARC Model 303A hanging mercury drop electrode. The result showed that whereas the placental Cd and Pb levels in smokers were higher that those of nonsmokers, Cu and zinc levels were lower in nonsmokers. These results imply that smoking during pregnancy could be harmful for both the mother and the fetus.