Urethral pressure and power generation during coughing and voluntary contraction of the pelvic floor in healthy females.

A probe which permits continuous measurement of the related values of pressure and cross-sectional area in the female urethra was used to provide a quantitative description of the adjunctive occlusive forces in terms of pressure and power (mWatt) generation. Measurements were carried out at the bladder neck, midurethrally and distally in the urethra in 30 healthy women during coughing and squeezing. Statistically significant variations were found in pressure and power generation between the 3 sites of measurement both during coughing and squeezing. Power generation and the pressure increase were significantly greater during coughing than during squeezing along the entire length of the urethra. The presence of a dynamic active closure mechanism was demonstrated at the bladder neck in addition to that located midurethrally. This bladder neck mechanism is thought to be due to the vagino-levator sling system (the urethral supports).