Healthy, middle-aged, history-free, continent women--do they strain to void?

We evaluated to what extent abdominal straining is used for voiding in an asymptomatic, continent, healthy, middle-aged female population.

A total of 32 women (mean age 49 +/- 6 years old) could be prospectively included. Technical investigations consisted of flowmetry, pressure flowmetry with EMG and electrosensation evaluation. Some data were compared with those of stress incontinent women investigated prospectively in the same way.

There were 4 women who were excluded from analysis because of abnormal sensory evaluation. The symptom-free participants voided with low detrusor pressure, a high flow rate and no residual. A large segment (42%) used additional abdominal straining to void on cystometry and reported that such straining was their usual habit for voiding at home. Straining was seen as frequent in women with stress incontinence. However, significantly more women with stress incontinence used straining without detrusor contraction.

These healthy middle-aged women without a history of pelvic surgery, or symptoms or signs of urological, anorectal or gynecological problems, voided with a mean Pdetmax of 25 cm H(2)O, mean Qmax of 29 ml per second, and the majority without residual. Many of them strained during detrusor contraction and this had not led to the development of signs or symptoms. The way straining is done may make the difference in that during reflex bladder contraction and urethral relaxation, additional straining may have little negative effect. If straining is used to void without the initiation of the micturition reflex, voiding dysfunction and incontinence might develop more easily.