It’s not relevant to the position he’ll be taking. He can make no change whatsoever to abortion law as vice-president unless there’s a 50-50 tie. Ryan is clearly pro-life and can be judged on his record in congress. Romney and his advisers are trying to get everybody on the same policy page (which is totally stupid but whatever).
Yes, I know, we've been hearing for forty years how it doesn't matter if certain people are pro-abortion or not. That might help explain why nearly 4000 babies are being slaughtered each day.