Effects of iron supplementation on maternal hematologic status in pregnancy

Objectives. Prenatal iron supplementation has been the standard recommendation for reducing maternal anemia in developing countries for the past 30 years. This article reviews the efficacy of iron supplementation on hemoglobin levels in pregnant women in developing countries. Methods. Data from randomized controlled trials published between 1966 and 1998 were pooled. Meta-analyses of the relative change in maternal hemoglobin associated with iron supplementation were stratified by initial hemoglobin levels, duration of supplementation, and daily gestational supplement dose and supplementation with other nutrients. Results. Iron supplementation raises hemoglobin levels. Its effects are dose dependent and are related to initial hematologic status. The extent to which iron supplementation can reduce maternal anemia is unclear. Conclusions. The extent to which maternal hemoglobin levels can be increased by recommended prenatal supplementation is limited and has uncertain physiological benefits. Other approaches, including food fortification and prevention and treatment of other causes of anemia, require methodologically rigorous evaluation to find effective answers to this global problem.