Oral Contraceptives Lower Risk of Urinary Incontinence Symptoms

Will Boggs, MD

September 04, 2009

September 4, 2009 — Women of child-bearing age who use oral contraceptives face a lower risk of lower urinary tract dysfunction than women of similar ages who do not, say researchers from Sweden.

"Hormone intake in the form of oral contraceptives has the potential to positively influence bladder and urethral function," Dr. Daniel Altman from Karolinska Institutet Stockholm, Stockholm, Sweden told Reuters Health in an email.

In their study of female twins between the ages of 20 and 46 years who responded to a web questionnaire, Dr. Altman and his colleagues assessed the influence of contraceptives on the risk for lower urinary tract dysfunction.

Based on their responses, women with urinary dysfunction were classified as having either stress or urgency incontinence (or mixed incontinence, if they had both), overactive bladder, or nocturia. For the final analysis, however, these subtypes were combined into a single outcome variable.

In the August issue of Fertility and Sterility, the investigators report that of the 8689 twins who responded, 2072 were current users of oral contraceptives and 118 were using levonorgestrel-releasing intrauterine devices (IUD).

Current use of oral contraceptives was inversely associated with lower urinary tract dysfunction, even after adjusting for age, body mass index, and pregnancy, according to the researchers.

Use of oral contraceptives was associated with a 43% lower risk of stress urinary incontinence, a 48% lower risk of mixed urinary incontinence, and a 64% lower risk of urgency urinary incontinence.

There was an insignificant inverse association between oral contraceptive use and overactive bladder symptoms, the researchers note.

The protective effects of oral contraceptives were similar for mono- and dizygotic twins. There was, however, no reduction in symptoms for the IUD users.

Unfortunately, the authors admit, they did not collect information on duration of contraceptive use or time since their last use.

Even so, Dr. Altman told Reuters Health, his group's findings "further (strengthen) the notion that even though hereditary factors play an important role for the liability of developing urinary incontinence, the risk for incontinence is amenable to intervention."

"We have initiated a prospective follow-up study of the women in the article," he continued. "By collecting data 5 years after the baseline study we will hopefully get more information on the cause-effect relationship from women who have started using oral contraceptives during the observational period and compare it to women who have stopped taking 'the pill' or changed prevention method. Prospective data will also allow us to estimate the effects of duration-of-use, aging, childbirth, and other environmental risk factors which complicate the association."

Noting that the women in their study were all of reproductive age, the investigators point out that there is only conflicting evidence on the effects of hormone intake on lower urinary tract symptoms in women who are past menopause. Some consensus reports have supported this approach, but findings from the Women's Health Initiative, for example, do not support the use of oral contraceptives for treating urinary incontinence in older women.

"It seems biologically plausible that intake of female reproductive hormones influences periurethral connective tissue structure and metabolism differently before and after menopause," the researchers comment.

Also unknown, the authors conclude, is whether or not these hormones "may actually improve urinary incontinence symptoms in women with manifest disease."

Fertil Steril. 2009;92:428-433. Abstract

Reuters Health Information 2009. © 2009 Reuters Ltd.


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