Constriction of the levator hiatus during instruction of pelvic floor or transversus abdominis contraction: a 4D ultrasound study.

A new theory claims that the pelvic floor muscles (PFM) can be trained via the transversus abdominis (TrA). The aim of the present study was to compare the effect of instruction of PFM and TrA contraction on constriction of the levator hiatus, using 4D perineal ultrasonography. Thirteen women with pelvic organ prolapse participated in the study. Perineal ultrasound in standing position was used to assess constriction of the levator hiatus. Analyses were conducted off-line with measurements in the axial plane of minimal hiatal dimensions. The reduction of all the hiatal dimensions was significantly greater during PFM than TrA contraction. All patients had a reduction of the levator hiatus area during PFM contraction (mean reduction 24.0%; range 6.1-49.2%). In two patients, there was an increase of the levator hiatus area during TrA contraction. Instruction of PFM contraction is more effective than TrA contraction.