When your dog gives birth to her puppies, your dog should instinctively chew each pup out of his placental sac and bite the umbilical cord in half. Since a blood vessel flows through the umbilical cord, some bleeding may occur. You'll need to tie off the base of the umbilical cord and sterilize it to prevent infection once your dog has licked her new puppy dry. Keep intervention to a minimum, as too much human involvement during whelping can upset your dog.
Umbilical Cord Care
Tie off the umbilical cord using unwaxed dental floss or clean thread roughly 1 inch from the puppy's abdomen, taking care not to tug on the umbilical cord. Crush or tear the umbilical cord on the far side of the knot, which mimics the grinding or shredding your dog would do with her teeth. Sterilized, old, dull scissors work well to crimp and tear the umbilical cord. Other options include pinching and tearing the cord with your fingers or using a hemostat, a medical clamp that resembles long-nosed scissors. Whichever tool you choose, gently pinch and tear until the cord becomes severed. Dip the end of the umbilical cord in iodine or alcohol immediately after severing it.