Intravenous vs. Oral Iron for Anemia in Pregnancy: A Meta-Analysis of Efficacy and Safety

Abstract

Background: Iron deficiency anemia (IDA) remains one of the most prevalent nutritional disorders globally, particularly affecting pregnant women in low- and middle-income countries. While oral iron is the standard first-line treatment, its gastrointestinal side effects and poor compliance often limit effectiveness. Intravenous (IV) iron offers a faster alternative but carries potential risks and higher costs. Objective: To systematically compare the efficacy and safety of intravenous iron therapy versus oral iron supplementation for treating iron deficiency anemia in pregnant women, based on randomized controlled trial (RCT) data. Methods: A systematic review and meta-analysis were conducted following PRISMA guidelines. Databases including PubMed, Cochrane CENTRAL, and Google Scholar were searched from inception to 15 March 2025 for RCTs comparing IV and oral iron in pregnant women with IDA. Outcomes included change in hemoglobin (Hb) levels, risk of postpartum hemorrhage (PPH), need for blood transfusion, and adverse events. Risk of bias was assessed using the Cochrane Risk of Bias Tool, and evidence certainty was graded using GRADE. A random-effects model was used to pool results. Results: Ten RCTs (n = 5954) were included. IV iron was associated with a significantly greater Hb increase at 3–6 weeks post-treatment (SMD: 0.25; 95% CI: 0.01–0.49; P = 0.04; I² = 85%). Sensitivity analysis excluding high-weight studies showed stronger results (WMD: 0.36 g/dL; 95% CI: 0.24–0.47; P < 0.00001; I² = 27%). No significant difference was found in the risk of PPH (RR: 1.21; 95% CI: 0.77–1.89; P = 0.41) or need for transfusion (RR: 0.69; 95% CI: 0.46–1.03; P = 0.07). Adverse events were significantly lower in the IV iron group (RR: 0.51; 95% CI: 0.37–0.71; P < 0.0001; I² = 0%). Conclusion: IV iron is more effective than oral iron for improving hemoglobin levels in pregnant women with IDA and has a better safety profile. However, it does not significantly reduce the risk of PPH or transfusion. These findings support the selective use of IV iron in clinical scenarios where oral iron is poorly tolerated or ineffective. Further research is needed to evaluate long-term maternal and neonatal outcomes and cost-effectiveness in resource-limited settings.