Overweight and obesity causes low-grade systemic inflammation, which sharply increases risk for iron deficiency. Studies in our laboratory have shown that this is mainly the result of reduced dietary iron absorption because of increased hepcidin concentrations. During pregnancy, women have a large increase in iron needs because of the expansion of maternal blood volume and fetal needs. Iron deficiency anemia in infancy can impair cognitive development. Whether maternal adiposity impairs absorption and transfer of iron to the fetus, and thereby increases risk of iron deficiency in the mother and the infant is unclear.