Iron and folate supplements during pregnancy: supplementing everyone treats those at risk and is cost effective.

Iron and folate depletion in pregnancy Most women are unable to meet the demands of expanding red cell mass and fetal growth in pregnancy without depleting their stores of iron,3'5 and diet, even in developed countries, contains insufficient folic acid to prevent a reduction in tissue folate concentrations.67 As a result some pregnant women become anaemic. Supplements of 30-100 mg elemental iron and 100-300 ig folic acid daily are effective in maintaining iron stores and folate state and in raising the haemoglobin concentration in healthy pregnant women.6 8-" The incidence of anaemia has declined in Britain since the second world war, but the widespread use of iron and folate supplements has probably contributed; withdrawing routine prophylaxis would risk reversal of this trend.'2 Although few would dispute the efficacy of supplements in preventing the depletion of iron and folate and, indeed, in raising the haemoglobin concentration, the beliefs now exist that the apparent deficits are not harmful and that the average diet in the United Kingdom in the 1980s is sufficient in itself to ensure nutritional wellbeing of mother and fetus.'2 Indeed, many trials in developed countries have shown no benefit of iron and folate prophylaxis in relation to the outcome of pregnancy. In a widely quoted review only three out of 17 studies showed any benefit to mothers or infants from iron and vitamin supplements.'3 Many of the trials, however, had major drawbacks. Some excluded patients with a relevant outcome of pregnancy-for example, anaemia, premature delivery, antepartum haemorrhage. In others groups of patients were not comparable, and many included small numbers of patients. Caution should therefore be exercised in drawing firm conclusions from such data.