Abortion was legal, but wasn't it sort of extraordinarily dangerous? I mean, particularly a surgical abortion would have been, at that time.

For millennia there had been instructions and recipes for making abortifacient concoctions, to good or bad effect. Many of them are highly toxic to the mother herself. So many abortion-minded women faced the proposition of harming themselves to get at their unborn children.

And that is the premise of "legalizing" it: that it can be made "safe" and so they wouldn't need to use a coat-hanger in a back-alley "anymore" (although practically nobody did such things.)