You will definitely want to clean up your momma dog and her whelping area so that she and her puppies have a clean, dry environment. Your momma dog will usually take care of cleaning the puppies herself, but she may do so at the expense of cleaning herself, and you may need to help her clean up her own fur. She will definitely need your help to clean up her bedding. Doing so with as little interference as possible is best, so as not to disturb mom and puppies.
Bathing a new momma dog immediately after giving birth is generally not advised, as it takes her away from her pups, who need her care and body heat in the first few days after they are born.
Your mom dog may be exhausted, excited, stressed, anxious, and definitely messy after giving birth. Most momma dogs will not want to be separated from their puppies to have a bath, but your dog does need to be cleaned and have a clean bedding area for her and her pups. Cleaning up your dog and her environment with as little disturbance as possible will keep mom and pups healthy and happy.