Women who take oestrogen for several years appear to have a heightened risk of developing urinary incontinence, according to a new study.

As women approach the menopause, their body starts to make less of the hormone oestrogen and some people choose to take hormone replacement therapy (HRT) to replace the oestrogen that has been lost and reduce their symptoms.

But scientists at Emory University in the US believe the therapy may be associated with an increased risk of adult incontinence.

The research team analysed data on 167 postmenopausal women in order to investigate the relationship between oestrogen use and new cases of female incontinence.

None of the women were affected by urinary incontinence at the start of the study in 1993.

However, 47 women (28.1 per cent) reported uncontrolled urine loss when they were re-interviewed in 2004, including 31 women who were unable to engage in certain activities because of their incontinence.

Women who had taken oestrogen for at least five years were up to four times more likely to have incontinence than those who had taken it for less than five years or not at all.

Publishing their findings in the journal Menopause, the study authors concluded: "Postmenopausal community-dwelling women with a history of oestrogen use for five years or more were more likely to report newly incident urinary incontinence with condition-specific functional loss after ten years of follow-up."

Dr Gina Northington, who was involved in the study, told Reuters Health that a patient's history of oestrogen use may be an "important factor" in determining their risk of developing urinary incontinence.

The urogynaecology specialist advised women to discuss the pros and cons of oestrogen therapy before taking HRT.

"In addition to other risks associated with oestrogen, such as breast cancer and blood clots, this is another reason to make sure oestrogen is taken for the shortest amount of time, if it needs to be taken," she added.