More than a century it has been recognized as an essential iron and vital nutrient for humans to intervene in various physiological and metabolic processes. Worldwide, iron deficiency is the most widespread nutritional problem. In developing countries, about 50 % of pregnant women suffer from iron deficiency. According to the Encuesta Nacional de la Situacion Nutricional en Colombia conducted in 2010 (ENSIN) the overall prevalence of anemia in pregnant women in the sample was close to 18%. The purpose of this paper was to review the state of the art as a nutrient iron during gestation in women. Pregnancy is characterized by an increase in the formation of red blood cells due to plasma volume expansion, a condition that makes woman more susceptible to iron deficiency and the presence of iron deficiency anemia due to the high increase in its requirement. The absorption process is more efficient, performing a gradual increase of this during the progress of pregnancy, which is consistent with the needs of the growing fetus. Iron absorption will depend on the chemical form in which it is found in foods, being more available iron heme. However, although the nonheme iron is ingested in greater amounts in the diet of developing countries supplementation in pregnant women is a controversial topic that deserves further study and clear concessive.