Women who undergo a hysterectomy to treat heavy menstrual bleeding may have higher rates of urinary tract problems over the long term than those treated with the contraceptive device Mirena, a new study suggests.

The findings, published in the medical journal BJOG, do not mean that Mirena is the better treatment option for heavy menstrual.

But they suggest that the risk of urinary symptoms should be considered when women and their doctors are making treatment decisions, write the researchers, led by Dr. Satu Heliovaara-Peippo of Helsinki University Central Hospital in Finland.

The study followed 236 Finnish women between the ages of 35 and 49 who were treated for menorrhagia - heavy or prolonged menstrual bleeding estimated to affect about 10 percent to 20 percent of menstruating women.

Between 1994 and 1997, the women were randomly assigned to either undergo a hysterectomy - surgical removal of the uterus - or have the Mirena intrauterine device (IUD) placed in the uterus.

Mirena is a contraceptive, but is also approved for treating menorrhagia. The device releases a synthetic form of the hormone progesterone called levonorgestrel, which thins the lining of the uterus and reduces bleeding; some women who use the IUD stop having periods altogether.

Hysterectomy has long been established as an effective treatment for menorrhagia. But studies have come to conflicting conclusions as to whether the procedure raises a woman’s long-term risk of urinary tract symptoms, like incontinence and urinary tract infections (UTIs).

Among women in the current study, those who had a hysterectomy were more likely to have UTIs, incontinence or problems emptying the bladder in the 10 years after treatment.

At year 10, 48 percent of women in the hysterectomy group had stress incontinence - where urine leaks due to movements that put stress on the bladder, like lifting, coughing or sneezing. That compared with 34 percent of women in the Mirena group.

One-third of women who’d had a hysterectomy reported having at least one UTI in the five to 10 years following the procedure, versus 14 percent of women treated with Mirena. And at year five, 15 percent of women in the hysterectomy group said they felt they could not always completely empty their bladders, compared with 6 percent of the Mirena group.

When the researchers considered other factors that can affect the odds of urinary symptoms - like age, weight and smoking - hysterectomy remained linked to higher risks of UTIs and incomplete bladder emptying. The relationship with stress incontinence, however, was no longer significant in statistical terms.

Women and their doctors, according to Heliovaara-Peippo’s team, may want to keep the risks of urinary symptoms in mind when deciding on treatment for menorrhagia.

However, a range of factors determines which treatment option is best for any one woman - including the underlying cause of the menorrhagia, if it can be found, as well as a woman’s overall health and plans for having a child in the future.

Other treatment options for menorrhagia include birth control pills, oral progesterone and endometrial ablation - a procedure that destroys the lining of the uterus but leaves the organ in tact.

Mirena also carries its own risks. It has, for example, been linked to an increased risk of pelvic inflammatory disease - an infection that can lead to chronic pelvic pain or infertility - and it is generally not recommended for women with a history of PID. Less serious but more common side effects include ovarian cysts, headaches and acne.

The current study was funded by the Academy of Finland. None of the researchers reports any ties to Mirena maker Bayer Schering Pharma Oy.

SOURCE: BJOG, online February 15, 2010.