Bioavailability of Orally Administered Cadmium and Lead to the Mother, Fetus, and Neonate During Pregnancy and Lactation. An Overview

摘要

Some basic steps in the bioavailability pathways from diet to mother, fetus, and neonate during pregnancy and lactation are as follows: during pregnancy, (1) gastrointestinal absorption by the mother, (2) transfer from maternal blood to fetus via the placenta; during lactation, (1) gastrointestinal absorption by the mother, (2) transfer from maternal blood to milk via mammary glands, (3) gastrointestinal absorption from milk by the neonate. These pathways, functioning during pregnancy and lactation, are discussed as they relate to dietary exposure to cadmium and lead. Data presented indicate that important differences exist between the pathways for these two elements. Increased uptake and retention of cadmium by the mother during pregnancy and lactation occurs, with sequestration of cadmium in the maternal kidney, liver, placenta and mammary tissue; the fraction of maternal body burden transferred to the young is small. Increased uptake of lead by the mother during pregnancy and lactation also occurs. In the case of lead, however, a substantial portion of the lead absorbed from the diet by the mother is transferred to the fetus via the placenta and to the neonate via the milk. Toxicological implications of the bioavailability pathways discussed are assessed. (ERA citation 08:027667)