Iron supplementation in singleton pregnancy: Is there a benefit to doubling the dose of elemental iron in iron-deficient pregnant women? a randomized controlled trial.

OBJECTIVE: To assess the efficacy of doubling the 30 mg dose of iron in women with iron deficiency anemia (IDA) in singleton pregnancies. STUDY DESIGN: Prospective randomized controlled trial. Iron-deficient women were randomized during the second trimester to receive one or two capsules of daily iron supplement, containing 34 mg of ferrous sulfate, from 17 weeks until 6 weeks postpartum. The primary outcome was hemoglobin (Hgb) at 35 weeks. Secondary outcomes included ferritin at 35 weeks, Hgb during pregnancy and postpartum, birth weights, preterm birth rate, gastrointestinal side effects, intravenous iron administration and compliance. RESULTS: In all, 160 women were randomized to receive one capsule and 164 received two capsules. Both groups had similar Hgb (10.1 g dl-1) and ferritin (9.3 and 9.4 ng l-1) at allocation. Hgb concentration in both groups was similar at 35 weeks (10.8 g dl-1). There were no significant differences in any of the secondary outcomes. CONCLUSION: In IDA pregnant women, a single dose of iron is as effective as a double dose.