Placental transfer of lead in mother/newborn pairs of Maracaibo City (Venezuela).

The placental transfer of lead (Pb) from mother to newborn in seventeen pregnant women receiving medical care at Adolfo Pons Hospital, Maracaibo (Venezuela), is presented. Maternal blood was collected by venipuncture during the first stage of labor, while neonatal blood was taken from the umbilical cord vein; placental blood samples were obtained at the time of delivery. Lead determination was carried out by graphite furnace atomic absorption spectrometry. Blood Pb levels (mean +/- SD, microgram/L) of 53.2 +/- 31.8, 46.3 +/- 24.5 and 66.3 +/- 33.3 were found for newborns, placentas and mothers, respectively. Significant blood Pb correlations were observed. Results indicated that even when the mother had a low blood lead level the placenta did not have a restrictive barrier-type effect to protect against Pb transfer from mother to newborn. Neonates' blood Pb concentrations were much lower than the accepted upper limit of 250 micrograms/L Pb.