The Catholic Church used to be pro-choice until around the 19th Century. This is because the Bible did not really condemn abortion. Thomas Aquinas actually stated a fetus does not get its soul until several months after conception, which contradicts with modern (post 19th century) Catholic teaching that it gets a soul at conception. St. Augustus justified abortion on certain grounds.
Even though this requires a POD in the 19th century, the affects would really only be felt in the 20th.
How would a pro-choice Catholic Church affect the 20th Century?