Iron and folic acid deficiencies are the major causes of health problems among pregnant women and children, with a significant negative impact on economic and social development.From April 2002 to April 2003 at the Gilberto Mejía Mejía Hospital (Rionegro, Antioquia), the prenatal program was assessed for its impact on a cohort of pregnant women concerning knowledge of the following nutritional parameters: iron and folic acid functions, their source foods and bioavailability, supplement intake and tolerance, and globular indexes.A sample of 42 pregnant women was subjected to a nutritional education program along with the administration of a supplement consisting of 60 mg elemental iron, 400 microg folic acid, and 70 mg vitamin C. This formulation was prepared specifically for the study by Laboratorio Profesional Farmacéutico, LAPROFF. The effect of the educational program was measured by knowledge changes about how patient behaviours affect nutrient bioavailability via source foods intake, as well as recognition of the tolerance limits of supplements and potential effect of non-adherance. The physiological status of each patient was measured by three hematologic variables--hemoglobin, hematocrit, and ferritin.A positive understanding of how to improve nutritional practices was observed. With the supplements, 94.4% of women did not show anaemia at the end of pregnancy. These results agree with those in other, similar populations and indicate that implementation of prenatal control programs by educational and supplement administration is worthwhile.