A Cochrane review included 23 studies involving approximately 3 198 women. Oral iron in pregnancy showed a reduction in the incidence of anaemia (one trial, 125 women; relative risk 0.38; 95% Cl 0.26 to 0.55). Although iron treatments consistently increased maternal haematological indices in women diagnosed with iron-deficiency anaemia in pregnancy, no evidence was found that these laboratory improvements reflected in clinical improvements such as reduced preterm delivery, reduced infant low birthweight, lower rates of pre-eclampsia, sepsis or postpartum haemorrhage and its complications. Gastrointestinal adverse effects were more frequent with oral iron treatments, compared with other routes of iron administration. Compared with oral iron, intramuscular (IM) iron sorbitol and iron dextran improved haematological values, reduced the proportion of women with anaemia, and resulted in lower gastrointestinal side-effects, but these preparations were associated with higher rates of systemic reactions especially with IM iron. The findings also suggested that intravenous (IV) iron sucrose is effective, but there was uncertainty whether it increased the incidence of serious adverse effects such as thrombosis, which was frequent (9/41; 22%).