I have no experience in breeding rats, but if I were you I'd take her to the vet. I do have experience in breeding Miniature Donkeys and Pygmy Goats (strange, I know). A few years back I lost one of my breeder goats after she gave birth to one kid because I hadn't realized she had twins but one was stuck. By the time I got her to the vet it was too late for both her and the other twin. If there's a chance that the babies are stuck, I wouldn't risk it.