If an adult dog suddenly urinates while sleeping, it may be a problem with the urinary system. It is best to take the dog to the pet hospital for examination in time to avoid delaying treatment; if it is a newborn dog that suddenly urinates while sleeping, This is normal because puppies are relatively small and cannot hold their urine. It is best not to let the dog eat before going to bed to avoid the dog wanting to urinate and defecate in the middle of the night.