Expert Commentary

Is oral or IV iron therapy more beneficial for postpartum anemia?

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IV iron is the better choice for a select group of women. In a systematic review that evaluated more than 1,000 women who received oral iron versus 1,000 women who received intravenous (IV) iron for postpartum anemia (defined as hemoglobin level less than 12 g/dL), IV iron preparations were more effective in raising hemoglobin levels (almost 1 g/dL higher) at 6 weeks postpartum and were better tolerated than oral iron.




Sultan P, Bampoe S, Shah R, et al. Oral versus intravenous iron therapy for postpartum anemia: a systematic review and meta-analysis. Am J Obstet Gynecol. Published online December 19, 2018. DOI:10.1016/j.ajog.2018.12.016.

Iron deficiency anemia in pregnancy is associated with increased risk for adverse birth outcomes, including preterm delivery, cesarean delivery, and need for blood transfusion.1,2 Although the outcomes with postpartum iron deficiency anemia are more difficult to study, this condition is associated with increased risk of maternal fatigue and depression, and it is often overlooked as a significant issue during the postpartum period.

In a recent systematic review, Sultan and colleagues sought to provide an updated assessment of IV versus oral iron treatment for postpartum anemia. The 6-week postpartum hemoglobin concentration was the primary outcome.

Details of the study

The authors screened 2,744 articles for randomized controlled trials (RCTs) comparing oral and IV iron in the treatment of postpartum anemia. Fifteen RCTs were included in the review, with 1,001 women receiving oral iron therapy and 1,181 women receiving IV iron. The baseline postpartum hemoglobin concentration in the 15 studies ranged from less than 8 g/dL to 10.5 g/dL.

In all but 1 study, the women in the IV treatment arm experienced a significant increase in postpartum hemoglobin concentration, with the mean difference being 1.0 g/dL at postpartum week 1 (95% confidence interval [CI], 0.5–1.5; P<.0001) and 0.9 g/dL at postpartum week 6 (95% CI, 0.4–1.3; P = .0003).

Only 4 studies were included in the meta-analysis; specifically, 6-week postpartum hemoglobin levels were measured in 251 women who received IV iron and in 134 who received oral iron. Significant differences were seen in the IV iron group compared with the oral iron group for 3 of the secondary outcomes evaluated: flushing (odds ratio [OR], 6.95), decreased constipation (OR, 0.08), and decreased dyspepsia (OR, 0.07).

None of the other secondary outcomes associated with IV iron (muscle cramps, headache, urticaria, rash, or anaphylaxis) occurred at statistically significant rates. Notably, adherence was not assessed in the majority of the studies. Although constipation was increased in the oral iron therapy group, it was reported at only 12%.

Study strengths and weaknesses

Results of this study support previous findings that IV iron is better tolerated, with fewer gastrointestinal adverse effects, than oral iron, and they re-emphasize that IV iron therapy is both safe (the authors identified only 2 cases of anaphylaxis) and effective in improving hematologic indices.

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