Association of Maternal Serum Zinc Level with Neonatal Birth Weight in Term Deliveries

Abstract

Background: Zinc is an essential micronutrient involved in cellular growth, protein synthesis, and immune regulation. During pregnancy, maternal zinc requirements increase, and deficiency has been implicated in adverse birth outcomes, including low birth weight (LBW). LBW remains a major public health concern in Bangladesh, where maternal malnutrition is prevalent. Objective: To investigate the association between maternal serum zinc levels and neonatal birth weight in term deliveries. Methods: This case-control study was conducted at the Department of Obstetrics and Gynaecology, Sir Salimullah Medical College Mitford Hospital, Dhaka, between August 2022 and July 2023. A total of 130 term pregnant women were enrolled, comprising 65 cases (mothers of LBW neonates <2500 g) and 65 controls (mothers of normal birth weight neonates ≥2500 g). Maternal demographic and obstetric data were collected, and serum zinc levels were measured immediately after delivery. Neonatal anthropometric parameters were assessed within 24 hours of birth. Data were analyzed using SPSS 25, with chi-square and t-tests applied for group comparisons, and Pearson’s correlation used to assess associations. Results: The mean maternal age was significantly higher in the case group compared to controls (30.89±6.10 vs. 27.03±5.33 years, p<0.001). No significant differences were observed regarding parity and mode of delivery between groups. Neonates of LBW mothers had significantly lower crown-heel length, head circumference, and ponderal index (all p<0.001). Zinc deficiency (<60 µg/dL) was markedly more prevalent in the case group (72.3%) than in controls (24.6%) (p<0.001). A positive correlation was observed between maternal serum zinc levels and neonatal birth weight (r=0.551, p<0.001). Conclusion: Maternal zinc deficiency and advanced maternal age were significantly associated with LBW in term neonates, whereas parity and mode of delivery showed no independent effect. These findings underscore the importance of early detection and correction of micronutrient deficiencies, particularly zinc, during pregnancy to improve neonatal outcomes in resource-limited settings.