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.

Altman and colleagues’ results contradict to some extent another report from Sweden published last year that used a different database. The Swedish National Gynaecological Surgery Registry covered about half of the country’s departments of gynaecology and obstetrics for 1997–2002, and followed up nearly 85% of 1022 women over 2 years after surgery. This study reported no difference in de-novo urinary incontinence symptoms between women who had undergone hysterectomy compared with controls (those treated by endometrial ablation).

More worryingly, Altman and colleagues come to opposite conclusions to two earlier studies by the same group. In 2003, Altman and co-workers interviewed 120 women due to undergo hysterectomy before and after surgery, and concluded that neither abdominal nor vaginal hysterectomy was associated with de-novo or deteriorating symptoms of urinary incontinence 1 year after surgery. In 2006, the prospective data were reanalysed with 3 years of follow-up, but the conclusion was the same—namely that total hysterectomy was not associated with an increase in urge or stress urinary incontinence even when allowing for factors such as age, parity, and number of vaginal deliveries.

So, what is the truth? It seems likely that a simple hysterectomy does not adversely affect bladder function at least initially, and indeed pre-existing symptoms may improve. If hysterectomy-induced urinary stress incontinence is a reality, it only becomes so several years after the surgery, as already suggested.12 Or perhaps it has nothing to do with hysterectomy, and women who agree to hysterectomy are just different in ways that we do not yet understand.

I declare that I have no conflict of interest.

References

_{JL Melville, W Katon, K Delaney and K Newton, Urinary incontinence in US women: a population-based study, Arch Intern Med 165 (2005), pp. 537–542.}

LV Swithinbank, JL Donovan and JC du Heaume et al., Urinary symptoms and incontinence in women: relationships between occurrence, age, and perceived impact, Br J Gen Pract 49 (1999), pp. 897–900.

HES Online, Main operations summary http://www.hesonline.nhs.uk/Ease/servlet/ContentServer?siteID=1937&categoryID=204 (accessed Oct 14, 2007)..

EO Babalola, AE Bharucha, CD Schleck, JB Gebhart, AR Zinsmeister and LJ Melton III., Decreasing utilization of hysterectomy: a population-based study in Olmsted County, Minnesota, 1965–2002, Am J Obstet Gynecol 196 (2007), pp. 214.e1–214.e7.

D Altman, F Granath, S Cnattingius and C Falconer, Hysterectomy and risk of stress-urinary-incontinence surgery: nationwide cohort study, Lancet 370 (2007), pp. 1494–1499.

R Thakar, Dispelling the myth-does hysterectomy cause pelvic organ dysfunction?, BJOG 111 (suppl 1) (2004), pp. 20–23.

R Thakar, S Ayers, P Clarkson, S Stanton and I Manyonda, Outcomes after total versus subtotal abdominal hysterectomy, N Engl J Med 347 (2002), pp. 1318–1325.

R de Tayrac, N Chevalier, A Chauveaud-Lambling, A Gervaise and H Fernandez, Is vaginal hysterectomy a risk factor for urinary incontinence at long-term follow-up?, Eur J Obstet Gynecol Reprod Biol 130 (2007), pp. 258–261.

MA Engh, L Otterlind, JH Stjerndahl and M Lofgren, Hysterectomy and incontinence: a study from the Swedish national register for gynecological surgery, Acta Obstet Gynecol Scand 85 (2006), pp. 614–618.

D Altman, A Lopez, C Falconer and J Zetterstrom, The impact of hysterectomy on lower urinary tract symptoms, Int Urogynecol J Pelvic Floor Dysfunct 14 (2003), pp. 418–423.