Also, religious groups that were traditionally very liberal/voted Democrat (e.x. Catholics) on social issues also broke off from the Democrats over abortion and reproductive rights related issues over the course of the '80s, which isn't to say they were specifically /for/ those things at any point, they just became something more political in the '80s.
I wouldn't really have said that 1991 was a clear date for the 'start' of that process, though. Perhaps more "When it got into full swing." The other thing is that the loss of large groups like the Catholics and the involvement of the Christian Right in general caused the Democrats to swing right as well, which means that even when the Dems were in power in the '90s their attitudes and the policies they enacted were often more conservative than they had been before RE: women's lib/rights/etc., even if they still supported most of the issues on paper.