Hormone replacement therapy (HRT) may worsen incontinence in postmenopausal women, a new study has suggested.
"Our main finding, which comes in particular from one huge trial, is that one type of HRT - systemic conjugated equine estrogen (CEE) - may make urinary incontinence worse," said June Cody, a methodologist at the Cochrane Incontinence Review Group at the University of Aberdeen in Scotland.
"In addition, in this large trial, women who did not have incontinence at first were more likely to develop incontinence than those who took a placebo," the researcher added.
The systematic review by Cody and colleagues also showed that significantly more women who used local (vaginal) oestrogen reported that their incontinence symptoms improved, compared to those who used a placebo.
However, said the researchers, that result came from small studies that might have had limitations.
Writing a report for The Cochrane Library, the researchers have highlighted the fact that millions of women experience incontinence - an involuntary and embarrassing leakage of urine that can lead to social isolation and even stigma.
There are several kinds of urinary incontinence, including stress and urge incontinence.
Stress incontinence can occur when someone is coughing or sneezing, while urge incontinence occurs when one feels a sudden strong urge to urinate.
"The original (2003) Cochrane review on incontinence grouped women according to different types of incontinence - stress, urge or mixed. In this update, we rearranged things to look separately at local or systemic delivery. We then honed in on the different types of oestrogen. When we looked at the research with CEE, it seemed to make all types of incontinence worse," Cody said