The aim of this study was to investigate the changes in nutritional habits, and also relationship among oxidative stress, iron deficiency anemia and some antioxidant enzyme activities during pregnancy. Twenty pregnant women in the first trimester, 20 pregnant women in the last trimester and 20 non -pregnant women (control group) were included in the study. The study groups were similar in terms of age and body mass index. None of the participants had any systemic disease or smoked. After having filled out the questionnaire about nutritional habits, the blood samples were collected, and the malondialdehyde (MDA) level and activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) enzymes were measured together with hemoglobin (Hgb), hematocrit (Hct), iron, ferritin and the mean erythrocyte volume (MCV) levels.The most frequent meat consumption was on every other day in controls, but once a week in the first and last trimester groups. In addition, the most frequent egg consumption was on every other day and once a week in contro ls, but rare in the first trimester group, and once a week in the last trimester group. Although iron and vitamin use was 10% and 30% in the first trimester group, it was 50% and 65% respectively in the last trimester group. The MDA level was higher, and t he SOD, CAT and GSH-Px enzyme activities were lower in both pregnant groups than controls. The Hgb and Hct values were lower in the last trimester group compared to the controls and the first trimester group. The first trimester group and the controls were similar in terms of Hgb and Hct levels. There was no significant difference among groups in terms of ferritin, iron or MCV values.It was concluded that; a) the egg and meat consumption might decrease with the progress of pregnancy, b) the oxidative stress increased in pregnancy, c) Hgb and Hct values might be lower in the last trimester group despite increased intake of oral iron and vitamin supplements, and normal serum iron levels due to decreased CAT activity. Therefore, more studies are needed to demonstrate the relationship among oxidative stress, anemia and CAT enzyme activity in pregnancy.