The provision of iron supplements to pregnant women is one of the most widely practiced public health measures, yet surprisingly little is known about the benefits of supplemental iron for the mother or her offspring during fetal or postnatal life. The purpose of this article is to examine published information on the effects of anemia and iron deficiency on pregnancy outcome and to identify current gaps in the information.
A high proportion of women in both industrialized and developing countries become anemic during pregnancy. Estimates from the World Health Organization report that from 35% to 75% (56% on average) of pregnant women in developing countries, and 18% of women from industrialized countries are anemic (1). However, many of these women were already anemic at the time of conception, with an estimated prevalence of anemia of 43% in nonpregnant women in developing countries and of 12% in women in wealthier regions (1). The prevalence of iron deficiency is far greater than the prevalence of anemia and iron deficiency (low serum ferritin and sparse or absent stainable iron in bone marrow) often develops during the later stages of pregnancy even in women who enter pregnancy with relatively adequate iron stores (2). For this reason, and because of doubts concerning the benefits of iron supplementation on pregnancy outcome, there is uncertainty about whether routine iron supplementation of pregnant women is necessary.