Female urethral pressure profile; reproducibility, axial variation and effects of low dose oral contraceptives.

The variability of the female urethral pressure profile as determined with the microtransducer technique was studied in a group of healthy nulliparous women according to a standardized methodology. Estimation of the short term reproducibility, as well as investigation of which of several serially recorded urethral pressure profiles can be considered as most representative of the basal condition, was carried out by performing serial urethral pressure profile recordings within the same study session in 12 women. Estimation of the long term reproducibility and investigation of the influence of axial rotation of the transducer membrane on the measurements were carried out in 20 women who were on low dose oral contraceptives. No influence of low dose oral contraceptives on the urethral pressure profile measurements could be detected. When serial recordings were made within the same study session, the lowest values for the urethral closure pressure were generally observed in the 3rd and 4th recordings. The short term and long term reproducibility of urethral pressure profile measurements were generally the same for the measurements in both the supine and the sitting positions. Rotation of the transducer membrane as well as positional changes significantly influenced the urethral pressure profile recordings. The recordings in which the transducer was oriented ventrally generally showed a shorter urethral length and a higher closure pressure than those in which the pressure transducer was oriented laterally or dorsally. These observations as well as the observations made during dynamic testing indicate an asymmetrical distribution of urethral closure forces in healthy nulliparous women.