Essential Elements (Fe, Cu, Mn, Zn) in Meconium, and Newborn Length and Weight, in Relation to Maternal Lifestyle and Diet

<b>Background/Objectives:</b> Fetal exposure to essential metals, such as iron (Fe), zinc (Zn), copper (Cu), and manganese (Mn), is influenced by maternal nutrition and lifestyle during pregnancy, potentially impacting newborn health. This study aimed to quantify concentrations of these metals in meconium and evaluate their associations, together with newborn length and weight, in relation to maternal dietary and lifestyle factors. <b>Methods:</b> This cross-sectional study included 152 mother-infant pairs recruited from various regions of Split-Dalmatia County, Croatia. Meconium samples were collected within 24 h after birth and analyzed for Fe, Zn, Cu, and Mn concentrations. Maternal characteristics, dietary intake, supplement use, and lifestyle factors were collected via structured questionnaires and supplemented by hospital records. Associations among maternal factors, meconium metal concentrations, and newborn birth weight and length were assessed using non-parametric statistical methods. <b>Results:</b> Meconium concentrations of Fe, Zn, Cu, and Mn showed substantial interindividual variability, with a strong positive correlation between Fe and Cu. Higher maternal pre-pregnancy BMI was linked to lower meconium Fe, while BMI at delivery was associated with Zn. Dietary patterns influenced metal levels: higher fruit intake was linked to increased Cu, greater vegetable intake with lower Fe, and moderate tea consumption with higher Zn. No significant associations were found with maternal smoking, residence, or supplement use. Maternal meat consumption and higher pre-pregnancy BMI were both associated with higher newborn birth weight and length. <b>Conclusions:</b> Maternal BMI and specific dietary patterns during pregnancy significantly influence essential metal concentrations in newborn meconium and are associated with newborn size, highlighting the importance of balanced maternal nutrition and healthy metabolic status during pregnancy.