Changes in urethral cytology following estrogen administration.

Estrogen vaginal cream was given to 10 postmenopausal women with a diagnosis of genuine stress urinary incontinence. Clinical evaluation and urethral cytology from the midurethra were performed before and after 6 weeks of estrogen treatment. A favorable clinical response was obtained in 50% of the treated patients, in whom signs and symptoms of incontinence disappeared or significantly improved, by subjective and objective evaluation. Cytologic changes at the midurethra correlated well with clinical response to estrogens. Patients with a favorable response to treatment showed a positive 'maturation index' of squamous epithelium, changing towards more intermediate and superficial cells, and less transitional cells (p less than 0.05). Patients with a poor clinical response to estrogens had no significant change in urethral cytology after 6 weeks of therapy. Our results suggest that improvement or cure of stress incontinence after estrogen administration in postmenopausal women is achieved by affecting the 'urethral mucosal factor'.