The iron stores of 32 healthy pregnant women were evaluated longitudinally during pregnancy and 6 months post partum by serum ferritin assay and by bone marrow iron content. Half of the women were receiving oral iron while the others were not given iron supplementation.

Women receiving iron could maintain their iron stores throughout the pregnancy. By contrast, women without iron therapy had low serum ferritin values, pointing to the absence of iron stores during the last trimester, and 6 of these 16 women developed anemia. This was confirmed by estimation of the quantity of stainable iron in the bone marrow. In addition serum iron, transferrin and red cell MCV values indicated iron deficient erythropoesis.

During a 6-month period after pregnancy the women receiving supplemental iron during pregnancy had a significant increase in their serum ferritin concentrations, indicating restoration of iron stores. Women not receiving iron during pregnancy had exhausted iron stores at term and serum ferritin values stayed low even at 6 months after delivery. If iron therapy was instituted after parturition, serum ferritin assays indicated restoration of iron stores within the ensuing 6 month. To prevent iron deficiency anemia during pregnancy supplemental iron is advisable for all pregnant women in our country.