I thought the information in the quote below was interesting.
(A) significant number of Church fathers throughout history have held that abortion early in pregnancy was less serious than later on. From Augustine, to Jerome, to Aquinas, it was held that only once the body was formed, and the fetus became animated ("fetus animatus"), was abortion akin to murder. This seems to be the prevailing view by the 5th century. In the early 13th Century, Pope Innocent III held that "fetus animatus" began, and ensoulment occurred, at the time the woman first felt the movement of the fetus. In the 16th Century, Pope Gregory XIV put this at 16 1/2 weeks (116 days).

It wasn't until the 17th Century that the idea of "simultaneous animation", which held that ensoulment occurred at conception, began to gain more support. Then, in 1869, Pope Pius IX dropped the distinction between "fetus animatus" and "fetus inanimatus". In 1886, Leo XIII prohibited all abortions at any stage, even to protect the life of the mother, and required excommunication as punishment. And in 1917, Canon law was revised to refer only to "the fetus".
http://www.dailykos.com/storyonly/2009/3/6/104025/4951
While some parts of the religious community have long played emancipatory roles in history, it would appear that in this case, as science, suffrage movements and workers movements were overthrowing the way people understood their place in the world, the catholic church simultaneously reduced the rights of half their congregation (more if you consider that men are also affected by unwanted pregnancies) to control their bodies and lives. It would be interesting to know whether was a reaction to losing so much authority elsewhere. Anyone know?