I am concerned as well. Usually if 2 hours pass without producing a puppy you need to seek veterinary care for an emergency cesarean section. If she has not passed a puppy by now it is lodged most likely. Each puppy is in a separate sack and they need to stay in the sack until they come through the birth canal. At that time the mom will take care of removing the sac. I would go to an ER right away.
Please let me know if you have more questions.