IV Versus Oral Iron for Pregnancy Anemia: Meta-Analysis

Intravenous (IV) iron for iron deficiency anemia during pregnancy was associated with higher maternal hemoglobin and ferritin levels at delivery and a lower rate of blood transfusion than oral iron, according to a systematic review and meta-analysis published in JAMA Network Open.

Investigators pooled 29 randomized clinical trials involving 11,771 participants. The analysis compared IV and oral iron across formulations, with maternal hemoglobin and ferritin at childbirth as the primary outcomes. Secondary outcomes included transfusion during the delivery hospitalization, medication reactions, and neonatal measures. The review added 10 trials to an earlier analysis and excluded one trial that had been retracted.

Across 15 trials reporting hemoglobin at delivery, the IV iron group had a mean level 0.59 g/dL higher than the oral iron group (95% CI, 0.31-0.87). Maternal ferritin was higher by a mean of 50.93 ng/mL across eight trials (95% CI, 33.56-68.29). Neonatal ferritin also was higher with IV iron, by a mean of 21.38 ng/mL (95% CI, 5.50-37.25).

In 14 trials reporting transfusion, IV iron was associated with a lower transfusion rate during the delivery hospitalization (relative risk, 0.63; 95% CI, 0.49-0.82). In six trials with a mean pretreatment hemoglobin level of 9 g/dL or less, the relative risk was 0.58 (95% CI, 0.45-0.76). Mild adverse effects were less frequent with IV iron (relative risk, 0.56; 95% CI, 0.41-0.76); no serious adverse events were reported.

The authors cautioned that primary outcome results varied substantially across trials, which differed in iron formulations and dosing. They also noted possible publication bias and inconsistent outcome reporting. They concluded that the findings may support a greater role for IV iron in treating iron deficiency anemia during pregnancy.

Source: Sales SK, Rajprohat S, Simon L, et al. Intravenous vs oral iron for treating iron deficiency anemia in pregnancy: a systematic review and meta-analysis. JAMA Netw Open. 2026;9(9):e2630657. doi:10.1001/jamanetworkopen.2026.30657