Background: Iron deficiency (ID) remains the most prevalent nutritional deficiency globally, disproportionately affecting women of reproductive age (WRA) across socioeconomic strata. Despite its high prevalence, iron deficiency with or without overt anemia is frequently underdiagnosed and suboptimally managed in primary care settings, largely because it is perceived as an episodic rather than a chronic condition. Objective: This narrative literature review aims to synthesize current evidence on the epidemiology, pathophysiology, clinical manifestations, diagnostic approach, and management of iron deficiency in WRA aged 16–55 years, with a focus on reconceptualizing ID as a chronic, relapsing condition. Methods: A comprehensive literature search was conducted across PubMed/MEDLINE, Scopus, Web of Science, and EMBASE using terms including "iron deficiency," "iron deficiency anemia," "women of reproductive age," "ferritin," "menstrual blood loss," and "iron supplementation." Studies published between 2017 and 2025 in English were included. Key Findings: Iron deficiency affects an estimated 30–40% of WRA globally, with menstrual blood loss identified as the most common contributing factor. Serum ferritin below 30 ng/mL remains the most sensitive diagnostic marker. Oral iron is first-line therapy; however, adherence is limited by gastrointestinal side effects. Intravenous iron formulations demonstrate superior efficacy in selected populations. Long-term monitoring and preventive strategies remain inconsistently implemented. Conclusion: Reframing iron deficiency as a chronic condition requiring longitudinal management, rather than single-episode treatment, may substantially reduce the burden of disease in this population. Structured follow-up pathways and individualized management are essential.