Association Between Longitudinal Serum Ferritin and Gestational Diabetes Mellitus — Beijing, Shanxi, and Shandong PLADs, China, 2021–2024

What is already known about this topic? Elevated ferritin levels have been associated with increased insulin resistance, impaired insulin secretion, and heightened risk of type 2 diabetes in non-pregnant populations. However, the relationship between ferritin concentrations and the development of gestational diabetes mellitus (GDM) remains poorly understood. What is added by this report? This study identified a U-shaped association between serum ferritin measured at 11–13 weeks of gestation and GDM risk, demonstrating that both low and high ferritin levels predict increased GDM incidence. Additionally, elevated ferritin concentrations at 16–19 weeks and 24–27 weeks of gestation were independently associated with greater GDM risk. What are the implications for public health practice? These findings underscore the critical importance of monitoring serum ferritin throughout the first and second trimesters for early identification and prevention of GDM. Enhanced strategies are needed to improve clinical understanding and optimize the utility of ferritin assessment in prenatal care.