As your dog gets closer to her due date you will notice that she becomes increasingly uncomfortable. She will start nesting and resting more often. You have a better chance of recognising when she is overdue if you know when she was bred. However, the gestational period varies with different breeds. Some smaller dogs have shorter gestation periods, so do your homework or ask your vet for specifics. Most dogs of average size have pregnancies that last 63 to 67 days.
Behaviour changes are normal as your dog reaches the end of her pregnancy. If you notice any severe changes in behaviour, such as loss of consciousness, call your vet. An overdue dog sometimes will go into distress because something is stopping her body from delivering the pups naturally. This could be caused by a hormonal imbalance or a very small pelvis. Your dog will need surgery if she is not able to deliver her puppies naturally.
Sign of Stress
If your dog's pregnancy extends far past her due date, she will reach the point where she is not able to walk. She will lie down and not get up. Call your vet if time continues to pass and no puppies are born. She may need assistance. A pregnant dog should be able to walk up until delivery even if her abdomen is very large. If she can't walk, something is wrong or she is far past her due date.
If you know when your dog was bred you can determine her due date. Some dogs will go a few days past their due date, but if she is more than a week past she is seriously overdue. If she remains pregnant for too long. her puppies might die. The placenta becomes less effective at nourishing the puppies and may detach from the wall of the uterus, cutting off oxygen. This is rare, but some dogs do not go into labour naturally. The only option is surgical intervention.