Lead and trace element levels in placenta, maternal and cord blood: a cross-sectional pilot study

To determine lead (Pb) and trace element (Fe, Zn, Cu, Mg) levels in placenta, maternal and cord blood; further, to assess the interactions between Pb and trace elements, if any.

A cluster of 'at term pregnant women' from rural and urban areas (n = 30 each, total n = 60) as well as their neonates after delivery were recruited. Maternal blood, heel prick neonatal blood, placenta and cord blood were collected at the time of parturition. Pb and trace element levels in blood/serum, placenta were determined on graphite furnace atomic absorption (AAS) and flame AAS respectively. Due to sample constraints, only Pb levels were determined in heel prick blood samples of neonates.

There were no major abnormal signs and symptoms, however, 38% had pale conjunctiva and 13% had pigmented tongue. The blood lead levels (BLL) were significantly (P < 0.05) higher in urban post-partum women compared to their rural counterparts. Higher BLL did not correlate with either pregnancy outcome or neonatal anthropometry. Maternal serum trace element levels were deficient in both rural and urban women. Significant (P < 0.01) positive correlation between maternal and neonatal BLL as well as significant (P < 0.05) inverse correlation between cord BLL and placental Pb levels were observed. Maternal and cord BLL correlated inversely (P < 0.05) with maternal and cord serum Fe levels, respectively.

Urban post-partum women and their neonates were at higher risk with elevated BLL. Estimate of cord blood Pb may not be the true index of neonatal BLL. These observations must be confirmed in a larger cohort because prenatal/neonatal screening avoids the risks associated with rest of life.