I don't imagine there were many (if any) denominations who believe in the inspiration of Scripture who came out in favor of abortion. That is the curse of the Protestant church, a lack of belief in inspired Scripture, not a belief in Sola Scriptura.
Could you expand on that? I may be missing your point. Although I agree that there were many non-denominational quasi-Baptist churches (fundamentalist Bible-church types) that spotted the error right away. They just didn't get much press because they were single congregations. There were actually churches that were in favor of Roe (the idea, I guess, was fewer unwanted babies - but I cannot see it).
But on my original point. What Scriptural proof do we have that life begins at conception? My previous post was merely my opinion, I would love to see something definitive.