Daily oral iron supplementation during pregnancy.

Randomized and quasi-randomized trials evaluating daily oral iron, with or without folic acid or other micronutrients, during pregnancy. Participants were pregnant women of various ages and gestational ages; studies conducted worldwide; designs included parallel-group randomized trials and cluster-randomized trials; administration sometimes unsupervised; some trials included co-interventions such as deworming or vitamins.

Daily oral iron supplementation during pregnancy; 60 mg elemental iron per day with 400 micrograms of folic acid daily; started as early as possible after conception (no later than 3 months) and continued for the rest of pregnancy; if six months of supplementation cannot be achieved during pregnancy, continue postpartum or increase to 120 mg elemental iron daily during pregnancy in high-deficiency areas (WHO guidance).

Daily iron supplementation during pregnancy reduces risk of low birthweight and maternal anaemia/iron deficiency. In 11 trials (8,480 women) low birthweight <2500 g occurred in 8.4% of infants in the iron group versus 10.2% in controls (RR 0.81). Mean birthweight was higher by about 31 g (MD 30.81 g). Maternal anaemia at term (<110 g/L) reduced from 35.71% to 13.06% (RR 0.30); maternal iron deficiency at term reduced (RR 0.43). Iron supplementation also increased side effects, especially at doses above 60 mg daily; higher Hb concentrations during pregnancy and postpartum were observed; placental malaria was not increased. For iron plus folic acid versus folic acid alone, maternal anaemia at term improved (RR ~0.34) and infant outcomes were less consistently improved. Authors conclude daily iron is effective for reducing maternal anaemia and low birthweight, but dosing regimens should be updated to balance benefits and side effects, and malaria considerations should accompany iron programs in malaria-endemic areas.

Heterogeneity across trials; several trials at risk of bias; variable dosing and formulations; inconsistent outcome reporting; substantial attrition in some studies; settings include malaria-endemic and non-endemic areas and various co-interventions, limiting generalizability.