Weakness of the urinary sphincter or pelvic muscles (bladder outlet incompetence)

Hormone therapy (usually estrogen/progestin combination therapy taken by mouth), which can contribute to thinning of the pelvic muscles and supporting tissues

Blockage (bladder outlet obstruction)

Underactivity of bladder wall muscles

Medications with anticholinergic effects

Opioids, which seem to inhibit bladder contractility