This prospective study evaluates a target population of pregnant women at the time of pregnancy diagnosis to investigate the predictive value of serum ferritin (SF) levels for the later development of gestational diabetes mellitus (GDM). The intervention involves measuring early-pregnancy SF, transferrin, and hemoglobin levels, alongside HbA1c, and comparing these biomarkers between women who later develop GDM and those who remain normoglycemic. The primary outcome is to assess the success rate of this diagnostic regimen in identifying high-risk individuals, aiming to establish SF as a valuable early biomarker for GDM to enable timely interventions.