Maternal and Umbilical Cord Serum Zinc, Iron, and Copper Levels in Preterm and Term Neonates: A Prospective case control Study

Abstract

Background: Zinc, iron, and copper contribute to fetal growth, oxygen transport, enzymatic activity, and antioxidant defence. Their relationship with preterm birth remains uncertain, particularly in resource-limited settings. Objective: To compare maternal and umbilical cord serum zinc, iron, and copper concentrations between preterm and term neonates. Methods: This prospective case-control study was conducted during 2018–2019 at a rural tertiary-care hospital in Nellore, Andhra Pradesh, India. Fifty neonates born at 30–36 weeks of gestation and 50 term appropriate-for-gestational-age neonates were enrolled. Maternal venous blood and cord blood were collected at delivery. Serum zinc, iron, and copper were measured by atomic absorption spectrophotometry. Group comparisons used the unpaired t test or chi-square test, with statistical significance set at p<0.05. Results: Mean maternal zinc was lower in the preterm group than in the term group (77.12±23.22 vs 89.28±29.90 µg/dL; p=0.02), as was maternal iron (0.74±0.143 vs 0.87±0.197; p=0.05). Maternal copper did not differ significantly (98.74±22.37 vs 105.78±28.34 µg/dL; p=0.08). Cord zinc was lower among preterm neonates (89.40±18.13 vs 119.00±33.36 µg/dL; p=0.004), as was cord iron (1.53±0.478 vs 1.93±0.59; p=0.05); cord copper did not differ significantly (69.00±16.53 vs 73.00±13.50 µg/dL; p=0.13). Conclusion: Lower maternal and cord zinc and iron concentrations were associated with preterm birth in this study population. Copper concentrations did not show a significant case-control difference. Larger studies with antenatal sampling and multivariable adjustment are needed.