Is she getting close to delivery and how big is she? She might have the puppies pushing on her intestines and giving her the urge to go. You might want to put puppy pads down and when you see her going carry her to the pad. If she is to big bring the pad to her and tell her she is a good girl when she get stool on the pad. I would put the pad down where she commonly goes. You might have to do this or maybe take her out more while she is pregnant.