The response of the abdominal muscles to pelvic floor muscle contraction in women with and without stress urinary incontinence using ultrasound imaging

Aims To investigate the changes in the thickness of the abdominal muscles; measured by ultrasound, in response to pelvic floor muscle (PFM) contraction in women with and without stress urinary incontinence (SUI). Methods A total of 20 non-pregnant female participated in the study. Subjects were categorized into two groups: continent females (N = 10) and females with SUI (N = 10). The change in the thickness of the right transverse abdominis muscle (TrAM) and internal oblique muscle (IOM) was measured with ultrasound imaging during PFM contraction in both groups. Results There was an increase in thickness of the TrAM and IOM muscle during PFM contraction showing a co-contraction of the abdominals during PFM contraction both in women with and without SUI. No significant difference was found in the change in thickness of TrAM (P = 0.43) and IOM (P = 0.72) in response to PFM contraction between women with and without SUI. In overall, there was no statistical significant difference in co-contraction of abdominal muscles during PFM contraction between SUI women and healthy continent women. Conclusion It seems that co-activation of the abdominal muscles during PFM contraction exists in continent and stress incontinent women. Neurourol. Urodynam. 30:117–120, 2011. © 2010 Wiley-Liss, Inc.