USMI is the most common cause of leaking urine at rest in spayed female dogs (and occurs less often in males and cats).

 

The urethral “valve” (sphincter) doesn’t stay tightly closed between bathroom breaks, so urine dribbles—especially during sleep or relaxation.

 

First-line medicines help most dogs; for tough cases, minimally invasive urethral bulking injections, suspension surgeries (urethropexy/colposuspension), or a hydraulic/artificial urethral sphincter can restore continence for many patients.