It's a little more complicated than that. In the beginning, there
was 'abortion.' Then came 'anti-abortion.' But rather
than be seen as anti-something, the anti-abortion crowd
wanted to be pro-something, so they euphemized anti-abortion
into prolife. The pro-abortion crowd, seeing the
chance to escape the negative aspect of abortion,
switched to pro-choice in emphasis of a woman's
right to choose. And there it remains. If anything was
won, it was Roe v Wade.