Intravenous or oral iron for treating iron deficiency anaemia during pregnancy: systematic review and meta-analysis.

Objectives: To compare the effects on perinatal maternal and neonatal outcomes of intravenous and oral iron therapy as first-line treatment of iron deficiency anaemia (IDA) in pregnant women.

Study Design: A meta-analysis, applying fixed and random effects models, of randomised controlled trials (RCTs) that compared the effects of intravenous and oral iron therapy for pregnant women with IDA.

Data Sources: MEDLINE, EMBASE, Scopus, Cochrane Register of Controlled Trials, Web of Science; bibliographies of identified articles.

Data Synthesis: Fifteen eligible studies with a total of 1938 participants were identified. Each was at high risk of bias in at least one domain; ten were undertaken in low or middle income countries. Evidence (from nine RCTs) that intravenous iron was superior to oral iron in reducing the need for blood transfusion at delivery was low quality (Peto odds ratio, 0.19 [95% CI, 0.05-0.78]; number needed to treat, 95 [95% CI, 81-348]). Evidence that intravenous iron was superior to oral iron in increasing neonatal birthweight (eight RCTs: mean difference, 58 g; 95% CI, 4-112 g) or reducing the rate of breastfeeding cessation within 24 months of delivery (one RCT: hazard ratio, 0.70; 95% CI, 0.50-0.99) was of low or very low quality. While intravenous iron treatment was superior to oral iron for improving maternal haematological parameters at delivery, their effects on neonatal haematological parameters were similar.

Conclusions: There is no strong evidence that first-line therapy with intravenous iron is superior to oral administration for treating IDA in pregnant women. The few identified differences in outcomes were small in magnitude and from studies at high risk of bias.

Registration: International Prospective Register of Systematic Reviews (PROSPERO), CRD42019120652.