Iron Infusion During Pregnancy

What does the evidence say about IV iron infusion during pregnancy?

1. A current clinical review summarizing ACOG guidance says oral iron is first-line in the United States. IV iron may be considered for patients who cannot tolerate or do not respond to oral iron or who have severe iron deficiency later in pregnancy, and first-trimester safety data are absent. 1
2. WHO's 2025 context-specific recommendation favors IV over oral iron when confirmed iron deficiency anemia coexists with oral intolerance, inability to use or absorb oral iron, or a clinical need for rapid correction. It requires monitored administration with staff prepared for hypersensitivity reactions. 2
3. Formulations differ mainly in administration burden. Ferric carboxymaltose and ferric derisomaltose can deliver a complete replacement amount in one visit for many patients, while iron sucrose commonly requires several smaller infusions; the prescribed amount depends on the iron deficit and product limits. 1
4. A 2024 Cochrane review of 13 randomized trials comparing IV and oral iron for confirmed pregnancy anemia found modestly higher hemoglobin with IV iron and fewer gastrointestinal effects, but evidence for postpartum hemorrhage, transfusion, and other major clinical outcomes remained limited or uncertain. 3
5. In a multicenter Indian trial enrolling 4,368 singleton pregnancies at 14 to 17 weeks with moderate iron deficiency anemia, single-dose ferric carboxymaltose reduced low birth weight versus oral iron, but ferric derisomaltose did not. Neither IV formulation significantly improved the primary nonanemia outcome, so formulation findings were not interchangeable. 4

Is IV iron infusion safe in each trimester?

• First trimester. IV iron is generally avoided in the first trimester because pregnancy safety data for that stage are lacking. Confirm the cause of anemia and discuss oral iron or another stage-appropriate plan with the obstetric team.
• Second trimester. After iron deficiency anemia is confirmed, IV iron may be considered when oral iron cannot be used or has not produced an adequate response. Formulation choice affects whether replacement takes one visit or several infusions.
• Third trimester. Later pregnancy can make faster iron replacement more important when anemia is substantial or birth is approaching. The prescribed formulation, calculated iron need, infusion setting, laboratory follow-up, and delivery timeline guide the plan.