Effect of oral contraceptives intake on postural stability in young healthy women throughout the menstrual cycle.

The purpose of the study was to investigate the effect of oral contraceptives on static postural stability in young healthy women during their menstrual cycle. Twenty-three women with the regular menstrual cycle, using or not using oral contraceptives, participated in this study. Salivary progesterone and estradiol levels were measured during one menstrual cycle. Measurements of balance were performed during a quiet stance on a firm and foam surface by the force platform, with eyes either opened or closed, on day 2, 7, 14, 21 and 28 of the cycle. Results of stability on a firm surface with eyes opened showed a significant effect in the amplitude of body sway in the anterior-posterior direction since women using oral contraceptives had a lower amplitude compared to control women on day 28. During stance on a firm surface with eyes closed we showed only impact of the menstrual cycle on postural stability of women. In condition of stance on a foam surface with the eyes opened or closed no significant effects were found. Our results showed that oral contraceptives intake can improve the static postural stability before the onset of menstruation and decrease a risk of injury of young healthy women.