Eight parameters about iron nutrition were observed longitudinally in eighty pregnant women from the first trimester to delivery. Their nutrients intake were recorded at the same time. It was noted that serum iron store (ferritin) decreased markedly in the course of pregnancy and the incidence of iron deficiency increased. Total iron intake was closely related to the variation of these parameters, the degree of iron deficiency in pregnant women and the content of cord ferritin. Iron in maternal serum is correlated to ferritin in the cord blood. It suggested that natural food abundant in iron, or food fortified with iron should be taken in early pregnancy to prevent iron deficiency of mothers.