Pelvic floor muscle function in the standing position in women with pelvic floor dysfunction

Clinical assessment of the pelvic floor muscles (PFMs) in a standing position may provide a more valid representation of PFM function experienced by patients in daily life than assessment in the lying position. The primary aim of this study was to examine PFM function in a standing versus a lying position in parous women with any type of urinary incontinence and/or pelvic organ prolapse.

In this exploratory cross-sectional study, participant symptom status was determined using the Australian Pelvic Floor Questionnaire. Pelvic floor muscle function was assessed in standing and lying positions with a randomised order of testing. The primary outcome measure was vaginal squeeze pressure (VSP) using intra-vaginal manometry. Secondary outcomes included vaginal resting pressure, total PFM work and digital muscle testing. The difference between PFM function in a standing position compared with a lying position was analysed using paired t test or Wilcoxon's signed rank test.

Vaginal squeeze pressure assessed with manometry was higher in a standing than in a lying position (p = 0.001): standing (mean [SD]) 24.90 [12.67], lying 21.15 [14.65]. In contrast, PFM strength on digital muscle testing was lower in a standing position than in a lying position.

This study has demonstrated that PFM function in a standing position is different from that in a lying position in women with pelvic floor dysfunction. Whether the higher VSP observed in a standing position reflects a true difference in strength between positions, or a higher pressure reading due to incorrect PFM contraction technique in a standing position is uncertain. Further research with larger cohorts and a measurement tool that can accurately distinguish a rise in intra-vaginal pressure from PFM contraction rather than increasing intra-abdominal pressure is required to confirm this difference, and the clinical significance of any difference.