This is a very complex issue  

How would a state vote?

We could consider that states would vote along party lines, and today there is a even split between red and blue states.  That does not produce your 40-45 pro-choice states.

A lot of the issue depends on what you mean by pro-choice.  If that means abortion on demand and paid for by public funding, you will only have a very few states vote that way.  States today that allow late term abortions, if put to a vote would lose!  The country on a whole will not accept late term abortions!  If Pro-choice means an abortion would be allowed within a reasonable time period, such as most of Europe, such as in France (I think, it is 14 weeks).   Then Pro-choice may increase within the states, but NOT 40-45 states.

I have no idea were you could come up with a estimate of 40-45 states pro-choice,  voting history shows that most pro-choice ballots lose across the states, even in most of the blue ones.