Intravenous iron significantly increases maternal haemoglobin concentration before delivery in pregnant women with non-anaemic iron deficiency when added to routine oral prophylaxis, according to findings from a randomised clinical trial.
Background and Rationale
Non-anaemic iron deficiency during pregnancy is common, yet its optimal management remains uncertain. Current antenatal care guidelines recommend prophylactic oral iron, even though iron stores may already be depleted in women with normal haemoglobin concentrations. Whether intravenous iron offers additional benefit in this population has been unclear. To address this gap, investigators conducted a multicentre randomised trial to evaluate the effect of adding intravenous iron to standard oral iron prophylaxis on maternal haemoglobin outcomes before delivery.
Study Design and Methods
The two-arm trial was conducted at three teaching hospitals in Lahore, Pakistan. Pregnant women aged 18 years or older with singleton pregnancies were screened at their first antenatal booking visit. Eligible participants had non-anaemic iron deficiency, defined as haemoglobin 11–13 g/dL with ferritin concentrations below 30 μg/L. Women with high haemoglobin concentrations were excluded. Participants were randomly assigned in a 1:1 ratio during the second trimester to receive either a single 1000 mg dose of intravenous iron alongside routine oral iron prophylaxis, or standard care consisting of 30 mg oral iron daily throughout pregnancy. Outcome assessors were masked to treatment allocation. The primary outcome was change in maternal haemoglobin concentration from baseline to 36 weeks’ gestation, analysed using the intention to treat principle.
Key Findings
Between January 2020 and August 2023, 600 women were enrolled and followed up until delivery. Before delivery, mean maternal haemoglobin concentration was higher in the intravenous iron group compared with the oral prophylaxis group: 11.6 g/dL versus 10.8 g/dL. The mean difference was 0.74 g/dL; 95% CI: 0.64–0.85; p<0.0001, demonstrating a clear benefit of intravenous iron. Preterm delivery occurred in 14 women in the intravenous iron group and 21 in the oral iron group. Importantly, no serious or life-threatening adverse events were reported in either group, including anaphylactic shock or cardiovascular complications.
Clinical Implications
These findings suggest that intravenous iron is an effective and safe strategy to improve maternal haemoglobin levels in women with non-anaemic iron deficiency during pregnancy. The results support consideration of ferritin screening in early pregnancy to identify women who may benefit from targeted intravenous iron therapy, rather than relying solely on universal oral iron prophylaxis.
Reference
Wasim T et al. Intravenous iron for non-anaemic iron deficiency in pregnancy: a multicentre, two-arm, randomised controlled trial. Lancet Haematol. 2026;13:1:E22-9.
