OBJECTIVES: Our study focused on revealing difficulties in maintaining balance during pregnancy. METHODS: Balance testing was performed on 150 volunteers (50 healthy pregnant, 50 pathologically pregnant, 50 healthy young non – pregnant women). One hundred pregnant women were allocated into 4 subgroups based on physical activity performed prior to and during pregnancy. During stabilometer measurements static balance was examined with Romberg test while dynamic balance with 5 programs on a stabilometer. Statistical data were calculated according to mean, standard deviation and T-test while the results were considered to be relevant at p<0,05. RESULTS: Average results of Romberg test were worse in groups of pregnant women compared to non-pregnant women although the difference was not significant. Concerning the subgroups: those who had previously been involved in professional sports and were healthy and physically active during pregnancy performed better on the open–eye test (p<0,05) compared to pathologically  pregnant patients. Between the second and third trimesters of healthy pregnancies no significant results were found in Romberg test while a significant difference was detected (p<0,05) in the performance of the 5th exercise of the dynamic balance test. Regarding the 5 programs on the stabilometer examining dynamic balance non-pregnant women performed all exercises significantly better (p<0,05) than healthy pregnant women. However when compared to pathologically pregnant women apart from the exercises No.2 the result showed a significant difference (p<0,05). Concerning the same exercises healthy pregnant women performed significantly better (p<0,05) in exercises No.1 and No.4. Pregnant women who had previously been and remained physically active during pregnancy performed the exercise of moving the centre of body weight in a significantly shorter time than those who were inactive and hospitalised. CONCLUSIONS: Statistical analysis of data proves that physical activity (especially professional sports) prior to becoming pregnant and physical activity during pregnancy have positive effects.