Aim: to analyze the changes in the width of selected veins in the lower limbs during pregnancy and puerperium, with or without venous insufficiency(VI) diagnosed at the first trimester. Material and methods: the group of 100 pregnant was divided into two subgroups with or without VI. The examination was performed, namely between 11-14th, 18-22nd, 28-32nd weeks of gestation and in 6th week of the puerperium. The sonographic examination included the measurement of the transverse diameter (TD) of the common femoral vein (CFV), the superficial femoral vein (SFV) and the popliteal vein (PV). The changes in the vessel width during pregnancy and puerperium were compared in both groups. Moreover, the changes of analyzed ultrasound parameters between the two groups in the 4 analyzed time periods were compared to the first trimester results. Results: there was a statistically significant increase in the TD of CFV with the highest values in the third trimester and significantly higher in the puerperium compared to the first visit. TD in all analyzed stages of pregnancy in the group with VI was significantly higher. SFV and PV were not statistically different between the groups in any of the analyzed periods. Average TD of these vessels was higher in the third trimester, decreasing gradually during the postpartum period. Conclusions: The average TD was highest in the third trimester, decreasing during the postpartum period. In VI group a full return of TD to the values observed in the first trimester was not observed in the puerperium.