To provide instruction for pregnant women regarding adequate and balanced nutrition and determine whether iron and folic acid supplementation is essential. The research was an experimental clinical intervention. The study was conducted between March 2004 and May 2005 with 80 pregnant volunteers. The study participants were in their 16th to 24th weeks of pregnancy; all participants were healthy, carried only one fetus, and successfully completed their pregnancy. All participants were instructed about adequate and balanced nutrition. Until the participants gave birth, 40 (Group 1) consumed an iron-rich diet that was equivalent to the inclusion of a supplement containing 100 mg Ferro III plus 0,35 mg folic acid; the other group (Group 2) was also instructed in proper nutrition and was given by a gynecologist 1 tablet (100 mg) Ferro III hydroxide polymaltose complex and iron pharmaceutical with 0,35 mg folic acid (Maltofer Fol). In both groups, before and after the instruction, consumption frequency was noted, and the levels of serum ferritin, serum iron, total iron-binding capacity, folic acid, and vitamin B12 in the blood were determined at monthly intervals. Between the two groups, no statistical difference was found with regard to age, number of pregnancies, weight before pregnancy, body mass index (BMI) before pregnancy, and weight of the newborn (p>0,05). At the end of the study, the hemoglobin, hematocrit, and serum ferritin levels decreased considerably in both groups compared to the initial values (p<0.01). No statistically significant difference in serum ferritin levels could be found between the two groups (p>0,05). The comparison of Group I and Group II in terms of nutritional status (average energy and food consumption) in the pre-instruction and post-instruction periods revealed that intake of total protein, heme protein, dietary fiber, folic acid, carotene, vitamins A, B1, B2, B6, C, and B12, potassium, calcium, phosphorus, iron, and zinc was higher in Group I in the post-instruction period (p=0.000); no statistically significant change in nutritional status during pregnancy was observed in Group II. Conclusion: Medical diet programs with iron sources are examined in association with food consumption. Assessment of hematological results suggests that, during pregnancy, each patient should receive a specific dose, rather than a routine dose, of iron and folic acid.