If your Chihuahua is in labor and having contractions and does not deliver the puppy in an hour, then there is something wrong. The puppy may be stuck, the puppy can be too large for her to be able to deliver on her own, the puppy may be breach (coming out feet first). Don't let is go more than 1 hour, because if you do, she and her puppies can die, if you don't move fast enough. Take your dog immediately to the vet, because she will need a C-Section in order to save her life and safely whelp (deliver) her puppies. Good Luck!