Purpose: Physical and hormonal modifications occuring during the pregnancy, can lead to an increase in postural instability and to a higher risk of falls during gait. The first objective was to describe the center of pressure (COP) during late pregnancy at different gait velocity. Comparison of nulliparous women with postpartum women were conducted in order to investigate the effects of pregnancy. The second objective was to analyse COP variability between pregnant and non-pregnant women in order to investigate the effects of pregnancy on gait variability. Methods: Fifty-eight pregnant women in the last four months of pregnancy, nine postpartum women and twenty-three healthy non-pregnant women performed gait trials at three different speeds: preferred, slow and fast. Results: In the last four months of pregnancy gait velocity decreased. During the pregnancy, gait velocity decreased by 22%, stopover time increased by 6–12%, COP excursion XY decreased by 5% and COP velocity decreased by 16% and 20% along the anteroposterior and transverse axes, respectively. After delivery, gait velocity increased by 3% but remained a lower compared to non-pregnant women (–12%). Intra-individual variability was greater for non-pregnant than pregnant women. Conclusions: COP parameters were influenced by pregnancy. This suggests that pregnant women establish very specific and individual strategies with the aim of maintaining stability during gait.