Holding urine for 12 hours in dogs can cause kidney disease and cause serious harm to the dog's body, because urine can form stones in the dog's body for a long time, leading to bladder bursting, kidney failure, etc. The dog should be guided to Drink water and take your dog out for exercise to promote body metabolism. If the dog's condition is serious, it is recommended to send the dog to a pet hospital for examination and treatment immediately.