Background Iron deficiency is the most common cause of anaemia in pregnancy worldwide. Iron treatment can be given by mouth, intramuscular or intravenous injection. Alternatively, blood transfusions and recombinant erythropoietin are also used. Objectives To assess the effectiveness of different treatments for iron deficiency anaemia in pregnancy (defined as haemoglobin less than 11 g/dl) on maternal and neonatal morbidity and mortality. Search methods Cochrane Pregnancy and Childbirth Group Specialised Register of Trial was searched. Date of last search: December 2000. Selection criteria Randomised controlled trials comparing treatments for iron deficiency anaemia in pregnancy. Data collection and analysis The search identified 54 trials. Five trials, involving approximately 1234 women, met the inclusion criteria. Trial quality was assessed. Study authors were contacted for additional information. Main results Oral iron treatment in pregnancy was assessed in one small trial (n=125), where it was compared with placebo. This showed a reduction in the number of women with haemoglobins under 11g/dl (odds ratio (OR) 0.12, 95% confidence interval (CI) 0.06 to 0.24) and a greater mean haemoglobin level 11.3g/dl compared to 10.5 g/dl (weighted mean difference 0.80, 95% CI 0.62 to 0.98). However, there were no data on clinically relevant outcomes. When comparing different iron treatments, the intravenous (IV) route of administration was associated with an increased risk of venous thrombosis (1 trial, n=74. Iron dextran intramuscularly (IM) versus IV (n=49) OR 0.13, 95% CI 0.02‐1.02. IM iron sorbitol‐citric acid versus IV iron dextran, OR 0.12, 95% CI 0.02‐0.94). Intravenous iron treatments were compared with placebo in one trial (n=54) but only scarce data on adverse outcomes were suitable for inclusion in this review. Authors' conclusions This review provides inconclusive evidence on the effects of treating iron deficiency anaemia in pregnancy due to the shortage of good quality trials.