Serum Levels of Vitamin D and Magnesium Among Pregnant Women at Usmanu Danfodiyo University Teaching Hospital, Sokoto, and Their Association with Preterm Delivery

Background: Preterm birth remains a leading cause of neonatal morbidity and mortality worldwide, affecting an estimated 15 million infants annually. Nigeria ranks among the countries with the highest burden of preterm births. Emerging evidence suggests that deficiencies in micronutrients such as vitamin D and magnesium may contribute to the risk of preterm delivery, although findings remain inconsistent. Objective: To determine the serum levels of vitamin D and magnesium among pregnant women at Usmanu Danfodiyo University Teaching Hospital (UDUTH), Sokoto, and assess their association with preterm delivery. Methods: This was a hospital-based comparative cross-sectional study involving 120 pregnant women in labour, selected using systematic random sampling. Participants were categorized into two groups: 60 women with preterm labor (28 to <37 weeks gestation) and 60 women with term labor (≥37 weeks gestation). Blood samples were collected for the estimation of serum 25-hydroxyvitamin D and magnesium levels. Statistical analysis was performed to determine associations between micronutrient levels and preterm delivery. Results: The mean serum vitamin D level was significantly lower in the preterm group compared to the term group (26.67 ± 14.97 ng/mL vs. 49.55 ± 18.10 ng/mL; p < 0.001). Low maternal vitamin D levels were significantly associated with an increased likelihood of preterm delivery (adjusted odds ratio [AOR] = 18.62; 95% CI: 2.75–9.49; p < 0.001). Similarly, the mean serum magnesium level was significantly lower among women with preterm labor compared to those with term labor (0.59 ± 0.21 mg/dL vs. 0.83 ± 0.21 mg/dL; p < 0.001). Women with hypomagnesemia (<0.65 mg/dL) had a significantly higher risk of preterm delivery (relative risk = 3.83; p < 0.001). Conclusion: Low serum levels of vitamin D and magnesium are significantly associated with preterm delivery. These findings highlight the potential role of micronutrient deficiencies in the pathogenesis of preterm labor. Recommendation: Routine assessment and appropriate supplementation of vitamin D and magnesium during pregnancy may help reduce the risk of preterm delivery. Further large-scale randomized controlled trials are recommended to validate these findings. Keywords: Vitamin D, Magnesium, Preterm delivery, Pregnancy, UDUTH, Sokoto