One of the best ways to know when your dog is done whelping is to have a puppy count X-ray done a few days before the birth. This way, you can count the number of puppies as she gives birth to each one. Apart from this, monitoring your bitch closely is important. Your bitch may enter a resting period between giving birth to each puppy. This can last for up to four hours. If she stops having contractions after four hours, it's likely that she has no more puppies. If you have any concerns about your dog's birthing process always talk to your vet.