Comparative Analysis of Lead Levels, Bone Metabolism, and Micronutrients in Pregnant and Non-Pregnant Women

Lead (Pb) toxicity remains a global health concern, disproportionately affecting vulnerable populations such as pregnant women and their fetuses. During pregnancy, physiological bone resorption can release stored Pb into the bloodstream, compounding risks of micronutrient depletion and adverse neurodevelopmental outcomes. A comparative cross-sectional study was conducted involving 78 pregnant women stratified by trimester and 31 non-pregnant women. Blood Pb levels, bone turnover biomarkers - pyridinoline (PYD), bone-specific alkaline phosphatase (bALP), and serum concentrations of essential micronutrients (zinc, copper, iron, total calcium, and free calcium) were measured. Group comparisons and correlation analyses were performed to elucidate the interactions among Pb, bone turnover, and micronutrient levels. Pregnant women exhibited significantly higher blood Pb levels compared to non-pregnant controls, peaking in the second trimester (35.48 ± 40.2 µg/dL; p < 0.001). PYD and bALP levels were elevated across all trimesters, indicating increased bone turnover. Zinc and iron levels declined significantly during pregnancy, with the lowest levels observed in the third trimester (Zn: 8.94 ± 0.9 µmol/L; Fe: 15.27 ± 3.9 µmol/L; p < 0.001). Notably, Pb levels negatively correlated with zinc (r = -0.403, p = 0.025) but positively correlated with copper in later trimesters (r = 1.000, p < 0.001). This study highlights critical interactions between Pb exposure, bone turnover, and micronutrient depletion during pregnancy, particularly during the second trimester. Elevated Pb levels and micronutrient deficiencies may pose significant risks to maternal and fetal health, underscoring the need for targeted interventions, such as nutritional supplementation and Pb exposure mitigation.