Steinauer JE et al. (2005) Postmenopausal hormone therapy. Does it cause incontinence? Obstet Gynecol 106: 940–945

Randomized, controlled trials have shown conflicting results on the effects of hormone-replacement therapy (HRT) and the risk of urinary incontinence in postmenopausal women. To try to clarify this issue, Steinauer et al. investigated the effects on incontinence of oral conjugated estrogen plus medroxyprogesterone acetate among 1,208 women, who had enrolled in the Heart Estrogen/progestin Replacement Study (HERS).

HERS was a randomized, placebo-controlled, double-blinded trial that evaluated the effects of HRT in postmenopausal women with coronary disease. Overall, 597 women who reported no loss of urine during the 7 days before baseline were assigned to HRT and 611 to placebo. Participants were initially followed up at 4 months and thereafter at 1-year intervals.

During 4 years of treatment, 64% of women taking HRT reported weekly incontinence compared with 49% of women in the placebo group (P <0.001). This difference was evident at the fourth month of follow-up and throughout the 4-year study period. The odds ratio for weekly incontinence in women taking HRT compared with placebo was 1.6 (95% CI 1.3–1.9; P <0.001). In women under 60 years of age, the effect of HRT on the risk of urinary incontinence was minimal.

The authors conclude that women over 60 years of age taking estrogen plus medroxyprogesterone acetate have an increased risk of urinary incontinence, and suggest that women considering this specific treatment regimen should be informed of the risk.