Hi Cheri,
I take the guide from my vet. If the mother is not in any distress then we would happily wait, but i am loath to wait any more than 48hrs past her due date. I have had a bitch welp 3 days late (although she started within 48 hours but first pup arrived at 72hrs) she had all pups naturally, & only 1 still born. She had a 27hr labour, delivering pups every couple of hours & having s drink, food & rest in between, delivering her last puppy 27hrs after the first ... ALIVE ...... If she is not in distress & happily feeding her pups, then we watch her closely & keep the vet informed how its going & administer meds if needed.