However, some medications are safe for use in pregnant dogs. Your vet may recommend administering vaccinations to your dog during her pregnancy, especially if your dog missed her last round of boosters. This could be a good idea, as your dog's unborn puppies are especially vulnerable to diseases including canine distemper, parvovirus, rabies and canine hepatitis. If your pregnant dog is exposed to any of these illnesses and hasn't been properly vaccinated, both her life and the ...