In Denmark, for example, serum ferritin concentrations at 2 mo postpartum in women supplemented during pregnancy were twice those of women who did not receive iron (35). A Finnish study showed that iron supplementation during pregnancy improved maternal serum ferritin, but not hemoglobin, concentrations for ≥6 mo postpartum (2). Compared with a placebo group, women in Niger who were supplemented with iron during pregnancy had higher concentrations of hemoglobin, serum iron, and serum ferritin; higher mean cell volumes; and lower erythrocyte protoporphyrin at 3 mo postpartum. At 6 mo postpartum, erythrocyte protoporphyrin was still significantly lower in the iron-supplemented group (31).