Oestriol in the prophylactic treatment of recurrent urinary tract infections in postmenopausal women.

A block randomized, double-blind, group-comparative, placebo-controlled study was conducted to assess the effect of oestriol on recurrent urinary tract infections in postmenopausal women. 40 women, median age 78 years (66-91), 20 in each group, were treated with oestriol three mg p.o. per day or corresponding placebo for four weeks, followed by one mg per day for eight weeks. The main response parameter was the number of urinary tract infections per week in the two treatment periods. Both oestriol and placebo reduced the number of infections per week significantly in both periods, compared with the pretreatment period. There was no difference between oestriol and placebo treatment in the first period. In the second period, however, oestriol treatment was significantly more effective than placebo (p = 0.05). Correspondingly, there was a significant difference between the two groups in the vaginal pH at the end of the study (p less than 0.05). We conclude that oestriol reduces recurrent urinary tract infections in postmenopausal women.