Since ERs are present in the trigone of the bladder and in the squamous epithelium of both the proximal and distal urethra, estrogen may increase the sensory threshold of the bladder and urethral closure pressure.10 The study by Hyun et al.11 suggested that the major cause of UI in postmenopausal women was the intrinsic sphincteric dysfunction related to altered connective tissue following estrogen deficiency, while the anatomical change was the most responsible factor of UI in premenopausal women.