Normally urinary incontinence is considered a problem of middle-aged and older women, especially those who've had a baby. But a study out today suggests even young women who've never been pregnant could suffer from the problem.

A new report published in Annals of Internal Medicine from Australian researchers is apparently the first study to look at the rate of urinary incontinence in the younger population. The study recruited healthy young women aged 16 to 30 on university campuses and at health clinics. The researchers asked the women to complete questionnaires about urinary incontinence during routine activities or sports, psychological well-being, physical activity, and health. They ended up with usable questionnaires from just over 1,000 women whose average age was 22.

About one in eight of the young women reported they'd experienced urinary incontinence.

Unlike previous studies, the researchers found no association between urinary incontinence and age, body mass index, physical activity, or past urinary tract infections. They say that could be due to the fact that the women in their study were relatively young, physically active and, for the most part, of normal body weight.

Women who had been sexually active but did not report use of oral contraceptives were more likely to report urinary incontinence than women with no history of sexual activity.

Urinary incontinence was also associated with lower psychological well-being. In previous research, "younger women have been shown to be subject to greater distress and restriction in activities from urinary incontinence than older women," the scientists wrote.

Researcher Susan Davis, PhD, chair of women's health in the Monash University department of medicine at the Alfred Hospital in Melbourne, says she and her collaborators had suspected that some women might be predisposed to incontinence without being pregnant. The study shows that this is apparently the case however it doesn’t establish clear reasons for this.

Possible reasons for the link between being sexually active and having urinary incontinence include the effects of intercourse and altered bacteria in the urogenital tract, according to the researchers.

Although other studies suggest urinary incontinence runs in families, this has yet to be backed up by solid genetic evidence.