The world record holder for a dog that gave birth (whelped) the most puppies is Tia, a neapolitan mastiff that had 24 back in June 2005. (Only 20 survived). Most dogs have considerably fewer puppies per litter. Dogs have a gestation time of 63 days, but the actual time to whelp the litter can seem just as long to the dog's owner. Mother dogs can take up to four hours between delivering puppies in the same litter, according to "Dog Owner's Home Veterinary Handbook." Determining when all of the puppies have finally been whelped can be difficult.
Watch the mother dog's behavior closely for four hours after the other puppies emerge. Note if she begins to strain, vomit, get restless or pants heavily in pain. These are signs that another puppy is on the way. Some dogs may whine, some lie on their sides while others will get into a crouch, according to Elizabeth L. DeLomba, DVM.
Call a vet immediately if the mother dog shows signs that another puppy is coming but suddenly gives up after an hour. The puppy could be stuck in the birth canal. "Dog Owner's Home Veterinary Handbook" notes that this usually happens with the first puppy of a litter, but it can happen for any puppy. The mother dog needs immediate veterinary help.
Collect all of the placentas from each puppy. Dogs will instinctively eat the placenta but a well-fed, well cared for mother dog does not need to do this. Placentas should come out immediately after a puppy and not before. If you have more placentas than puppies, one puppy may still be in the womb. Call the vet.
Relax after four hours have passed after the last puppy and the mother dog shows no sign of contractions or pain. Count the placentas again. If there are more puppies than placentas, then one placenta still needs to come out, but the vet can do that the next day unless the dog begins showing signs of stress.
Take the mother dog and puppies to a vet one day after whelping so the vet can be sure there isn't a placenta or a puppy still inside.