Reliability of Pelvic Floor Muscle Assessment with Transabdominal Ultrasound in Young Nulliparous Women

The aim of this study was to assess the reliability of pelvic floor muscles evaluation via transabdominal ultrasonography in young nulliparous women and to present the methodology for quantitative assessment of the ultrasound image of the pelvic floor muscles visible as displacement of the posterior wall of the bladder, caused by action of the pelvic floor muscles. The study comprised 30 young, Caucasian, nulliparous women (age 22-27; 168.6 ± 5.1 cm; 57.1 ± 11.8 kg) without pelvic floor muscle dysfunctions. The intra-rater, test-retest and inter-rater reliability of pelvic floor muscles evaluation was performed using transabdominal ultrasound at rest and during voluntary contraction. The reliability was assessed at three points of the image (at the middle, on the right and left side). The reliability of the three-point measurement of the pelvic floor muscles transabdominal ultrasound is excellent in the case of intra-rater assessments, both at rest (ICC = 0.98-0.99) and during contraction (ICC = 0.97-0.98); moderate at rest (ICC = 0.54-0.62) and poor during contraction (ICC = 0.22-0.50) in the case of test-retest assessment; excellent at rest (ICC = 0.95-0.96), and good during contraction (ICC = 0.81-0.87) in the case of inter-rater assessment. Transabdominal ultrasound is a reliable method of pelvic floor muscle evaluation. The three-points of assessment used in our study allowed for broader and more comprehensive imaging of the pelvic floor muscle, e.g., for quantitative detection contractility imbalances between the left and right side Due to the fact that understanding mechanisms of pelvic floor muscle functioning is crucial in the therapy of pelvic floor dysfunctions, therefore, reliable, valid tests and instruments are important.