Background: Preterm labor remains a major contributor to neonatal morbidity and mortality worldwide. Identifying predictive biomarkers such as maternal serum ferritin may enable early detection and improve perinatal outcomes. Methods: A case-control study was conducted at the Department of Obstetrics & Gynaecology, Dhaka Medical College Hospital, from June 2022 to May 2023. A total of 88 pregnant women were enrolled, including 44 cases with preterm labor and 44 controls with term labor, selected through purposive sampling. Sociodemographic and biochemical parameters were recorded, and serum ferritin levels were compared between the groups. Statistical analysis was performed using SPSS version 25. Results: The majority of participants in both groups were aged between 18 and 26 years. The mean age was slightly higher in the preterm group (25.59 ± 5.80 years) compared to the term group (24.56 ± 5.41 years), but the difference was not statistically significant (p = 0.331). Serum ferritin levels were significantly elevated in the preterm group (89.09 ± 106.07 ng/mL) compared to the term group (32.13 ± 31.40 ng/mL), with a statistically significant difference (p = 0.004). Correlation analysis revealed a significant negative association between serum ferritin levels and gestational age (r = –0.313, p < 0.05), with an R² value of 0.139, indicating a modest inverse relationship. Conclusion: Higher maternal serum ferritin levels are significantly associated with preterm labor and inversely correlated with gestational age. Serum ferritin may serve as a useful biomarker for predicting preterm birth risk, supporting its inclusion in routine antenatal screening protocols.