Perinatal Exposure to Heavy Metals and Trace Elements of Preterm Neonates in the NICU: A Toxicological Study Using Multiple Biomatrices

In this study we aimed to investigate the levels of selected heavy metals and trace elements (Hg, Pb, Cd, As, Mn, Se, and Cu) in three different biomatrices-maternal urine (Mu), neonatal urine (Nu), and cord blood-of preterm newborns born at less than 35 weeks' gestation who were staying in the NICU and their mothers, and the relationships of these elements with maternal and neonatal characteristics. Cord Pb, As, and Hg were significantly lower than in Mu, whereas Se and Cu were higher (<i>p</i> < 0.001). All elements were excreted more in Mu than in Nu (<i>p</i> < 0.001). Nu levels of Cd, Mn, Se, and Cu were lower, while As and Hg were higher than in cord blood. Nu metal excretion increased significantly over time (<i>p</i> < 0.001). Positive correlations were found between MuCu and NuCu (r_s = 0.35) and between maternal Se and maternal age (r_s = 0.41). NuHg, MuMn, and cord Mn showed negative correlations with penile length, and NuHg was also negatively correlated with anogenital distance. The first and second NuPb levels were positively correlated with birth weight percentile. The findings suggest transplacental transmission and ongoing exposure to heavy metals and trace elements in preterm infants, highlighting the importance of prenatal environmental exposure awareness for healthcare providers.