Intravenous iron improves pregnancy anemia

Intravenous iron outperformed oral iron for pregnancy-related iron deficiency anemia.
*Systematic review and meta-analysis of randomized trials; Level 1a (OCEBM).

Citation

Sales SK, Rajprohat S, Simon L, et al. Intravenous vs Oral Iron for Treating Iron Deficiency Anemia in Pregnancy. JAMA Network Open. 2026;9(9):e2630657. doi:10.1001/jamanetworkopen.2026.30657

Background

Iron deficiency anemia is common in pregnancy and is linked with worse maternal and newborn outcomes. Oral iron is often first-line, but side effects and limited absorption can reduce benefit.

Patients

Pregnant patients with iron deficiency anemia in 29 randomized trials, totaling 11,771 participants. Excluded studies enrolled nonpregnant patients, lacked a comparison group, used observational designs, were not in English, or had no usable data.

Intervention

Intravenous iron, using several formulations and dosing schedules.

Control

Oral iron, most commonly ferrous sulfate.

Outcome

Primary outcomes were maternal hemoglobin and ferritin at childbirth. Secondary outcomes included transfusion, medication reactions, cesarean delivery, and newborn outcomes.

Follow-up Period

Through delivery; some blood tests at 4 to 6 weeks after treatment.

Results

Outcome Finding with intravenous iron vs oral iron
Maternal hemoglobin at delivery (primary) Mean difference 0.59 g/dL higher (95% CI 0.31 to 0.87)
Maternal ferritin at delivery (primary) Mean difference 50.93 ng/mL higher (95% CI 33.56 to 68.29)
Blood transfusion during delivery stay Relative risk 0.63 (95% CI 0.49 to 0.82); NNT not calculable from reported pooled data
Newborn ferritin Mean difference 21.38 ng/mL higher (95% CI 5.50 to 37.25)
Overall mild medication reactions Relative risk 0.56 (95% CI 0.41 to 0.76)

Benefits for transfusion were strongest when pretreatment hemoglobin was 9 g/dL or lower: relative risk 0.58 (95% CI 0.45 to 0.76). No serious medication reactions were reported. Oral iron is the current first-line control in many guidelines.

Limitations

Trials varied in iron type, dose, anemia severity, setting, and reported outcomes. Primary results had high variation across studies, and testing suggested possible publication bias. Some maternal and newborn outcomes were underreported.

Funding

National Institutes of Health; some authors reported outside industry ties.

Clinical Application

Consider intravenous iron, especially for severe pregnancy anemia or oral iron intolerance; evidence may refine first-line treatment choices.