A female dog's gestation lasts about two months. Since a female dog may deliver one to 10 puppies in a normal litter, depending on the breed and breeding management techniques used, it can be difficult to know when a mother has finished delivering. You can use a combination of observations and signs to help know if your dog's labor is progressing well.
Feel the outside of your dog's abdominal cavity with your hands. With gentle pressure, you may be able to feel the shape of any puppies still in the womb.
Check around the puppies and mother for the placentas. After delivering each pup, the mother should also deliver a placenta for each puppy, reports Dr. Bari Spielman of PetPlace.com. If you do not see a placenta for each puppy shortly after delivery, this could indicate your dog is having a difficult labor and may not be able to deliver all her pups.
Time how long your dog strains and pushes without producing a puppy. Pushing and straining for more than an hour without delivering a puppy is a sign that a puppy may be stuck in the birth canal. Veterinarian Ron Hines recommends getting veterinarian assistance should this occur.