Caddie, like Kelly said, you can refuse one, because you don't know how things are going to stretch when the time comes. I had one with #1, but with the girls, I just tore a little, and both in different places to where the episiotomy was done.

I think (and Kelly, please correct me if I am wrong) it helps too depending on how you are positioned during the final stages of birth as to the pressure placed on the perenium IYKWIM?

Also, it would be a different birth altogether, so things will be different anyway.