Introduction: Hypertension occurs in 6 to 10 percent of pregnancies. It remains one of the most common disorders in pregnancy and the leading causes of maternal and fetal morbidity. The changes in blood vessel endothelium have impact on the pathogenesis of hypertension and preeclampsia. Aim: The aim of this study was to establish endothelin-1 and lipids peroxides content in blood during hypertension and the influence of vitamin C and E supplementation on the concentration of both parameters. Materials and methods: Two study groups (pregnancy complicated with hypertension, pregnancy complicated with hypertension treated with vitamins C and E) and a control group with uncomplicated pregnancies were distinguished. Blood samples from maternal peripheral venous circulation were collected and ET-1 and lipids peroxides levels were determined from the blood samples. Results: Concentration of endothelin-1 in the group with hypertension and with vitamin supplementation was increased (66.18 ± 26.66 pg/ml) in comparison with normal pregnant (36.50 ± 13.25) and hypertension group (41.02 ± 15.98). The difference was significant. Lipid peroxides concentrations were significantly higher in the group with hypertension (1.18 ± 0.69) in comparison with both groups – controls (0.73 ± 0.35) and the group with hypertension and vitamin supplementation (0.77 ± 0.42). Conclusions: No significant differences in the endothelin-1 level between healthy pregnant and pregnant women with hypertension were found. Vitamin supplementation decreases the concentrations of lipid peroxides.