Does hysterectomy cause urinary incontinence?

Female urinary incontinence is a common problem. For instance, a postal study from the USA in more than 3500 women reported a prevalence of urinary incontinence (defined as urinary leakage at least monthly) in 45% of women, including a quarter between the ages of 30 and 39 years and half between the ages of 50 and 90 years. An earlier study from the UK, also based on a postal questionnaire of more than 2000 women, found the prevalence of urinary incontinence to be 69%, with a social or hygienic effect in a third of cases. Although women do not always admit to urinary incontinence or seek treatment, there can be no doubt that a large proportion experience it.

Hysterectomy is a common operation. Apart from delivery by caesarean section, hysterectomy is the most frequent major operation that women undergo during their fertile years. There are major national variations in hysterectomy rates, and substantially fewer hysterectomies are being done in the UK and in parts of the USA than even 10 years ago, but many women still have their uteri removed surgically.

So, is there a link between the two? There can be little doubt that stress urinary incontinence predisposes to hysterectomy if only because many patients managed by abdominal surgery (eg, Burch colposuspension) undergo concurrent hysterectomy. But conversely, does hysterectomy itself predispose to urinary incontinence? This suggestion is debatable, and is the subject of the paper by Daniel Altman and colleagues in today's Lancet.

They analysed data from the Swedish Inpatient Registry for 1973–2003 in more than 640 000 women to assess whether hysterectomy for benign indications increases the chance of subsequently undergoing surgery for urinary stress incontinence. They concluded that hysterectomy by whatever route or type does indeed predispose women to requiring subsequent stress-incontinence surgery by a factor of almost 2·5 compared with age-matched non-hysterectomised controls. Most interventions occurred within 5 years of the hysterectomy. Not surprisingly, the risk seems to increase with the number of vaginal births and in those who had hysterectomy for prolapse. Interestingly, Altman also found that women who had hysterectomy were also more likely to undergo surgery for two unrelated conditions—hallux valgus and varicose veins—but not enough to explain the much greater use of surgery for urinary incontinence.

Altman and colleagues' results seem clear, but are they correct? The truth is that there have been many studies that looked at the after-effects of hysterectomy in terms of urinary symptoms and bladder function, but there is no consensus. Admittedly, previous studies have tended to be smaller with short follow-ups, but more than one have reported either no detrimental effect of hysterectomy or even benefits. Thakar and colleagues found increased bladder capacity and reduced urinary stress incontinence after abdominal total and subtotal hysterectomy on urodynamic testing, albeit after only 1 year of surgery. Tayrac and colleagues found no increased risk of urge or stress urinary incontinence after vaginal hysterectomy after an average follow-up of almost 5 years.