Pelvic Floor Muscle Assessment in Standing and Lying Position Using Transabdominal Ultrasound: Comparison between Women with and without Stress Urinary Incontinence

The aim of the study was to investigate pelvic floor muscle function in lying and standing positions, using transabdominal ultrasound, to determine if the difference in positions varies between women with and without stress urinary incontinence. This was a two-way mixed-design study. Thirty non-pregnant women participated in the study. The subjects were categorised into two groups: continent and incontinent. The amount of bladder base movement on transabdominal ultrasound was measured in two positions: crook-lying and standing. The testing position was randomly selected and the mean value of three maximal contractions (normalised to body mass index) was taken for analysis. The result of two-way mixed-design ANOVA revealed no significant interaction between continence status and test position for contraction (p=0.60). The main effect of test position on PFM contraction was statistically significant (p=0.02) but the continence status had no significant effect on bladder base displacement (p=0.11). The amount of difference in two positions was not significant between two groups (p=0.61). Bladder base displacement in a cranial direction is greater in the standing position compared to crook-lying position in females, both with and without SUI.