Introduction: Venous insufficiency in pregnancy is associated witch an increased risk of complications. Objectives: The aim of the study was to analyse the venous system changes of the lower limbs during pregnancy and puerperium with or without venous insufficiency. Material and methods: The research was carried out on pregnant women divided into two groups according to the presence or lack of venous insufficiency. The venous system was examined four times: between 11-14th, 18-22nd, 28-32nd gestational week and at the 6th week of puerperium. The doppler examination included the measurement of the blood flow velocity in selected deep veins of the lower limbs: common femoral vein, the superficial femoral vein and the popliteal vein. Consecutively, the changes in the blood flow velocity during pregnancy and puerperium were compared between groups and finally to the results obtained in the 1st trimester. Results: The analysis of the blood flow showed that the blood flow velocity was statistically lower in the group with venous insufficiency. Velocity changes in time showed, in majority of cases, a substantial reduction in the blood flow velocity in the third trimester in both groups. This blood flow velocity increases during the puerperium and does not differ from those observed in the first trimester. Thus, the tendency of changes in the blood flow velocity were similar in character in both groups. Conclusions: The pregnancy related changes in venous system of lower extremities showed the reduction of blood flow velocity with advancing gestational age and were more evident in pregnancy complicated by venous insufficiency.