Lead and cadmium in maternal blood and placenta in pregnant women from a mining-smelting zone of Peru and transfer of these metals to their newborns

The present study was carried out to determine the lead and cadmium concentration in maternal and umbilical cord blood and placental tissue and breast milk, evaluating forty deliveries with normal evolution of pregnant women living in a mining-smelting town in Peru. In this study, mean concentration of lead in the blood of both women and their neonates were 27.2 ± 15.9 and 18.5 ± 13.0 µg/dl, respectively with 83% of the women and 65% of the neonates having toxic levels. Mean cadmium concentrations in maternal blood were below the safe upper limit, but 45% of women had levels above 10 µg/dl. On the other hand, the mean cadmium concentration in umbilical cord blood was 12.0 ± 17.8 µg/dl, with 38% of neonates having levels above 10 µg/dl. The mean concentrations of lead and cadmium in maternal milk were 108.9 ± 69.4 and 5.6 ± 4.3 µg/dl, respectively. In addition, lead and cadmium in cord blood accounted for 67.8 and 136.4% compared to concentrations in maternal blood. There was negative relationship between the concentration of lead in the umbilical cord blood and the birth weight of the neonate (p = 0.006). From this study, it is evident that lead contamination and to lesser extent cadmium, pose a problem in pregnant women in this region. In addition, although the placenta appears to act as a protective barrier to the fetus, transfers of these metals to the fetus still persist. Furthermore, the concentration of lead was quite high in maternal milk and could be an important source of contamination to the infant. Finally, there was a negative association between the levels of lead in the umbilical cord blood and the birth weight.   Key words: Lead in umbilical cord blood, cadmium in umbilical cord blood, lead in maternal milk, cadmium in maternal milk, lead in placenta, cadmium in placenta, mining-smelting town.