An argument can be made that if abortion WAS murder, and prosecutable as murder, then every time an innocent woman had a miscarriage or stillbirth (which happens much more often than you realize), there would have to be a murder investigation (due to the possibility of the mom having induced the abortion somehow).

If the prospect of forcing millions of innocent women already suffering from a miscarriage through a trial (not to mention ALL the added cost and effort) doesn't horrify you, it should.

Secondly, over 50% of fertilized eggs never actually implant into the uterus and get washed out. If nature itself is tossing fully half of the fertilized eggs out, then a few more won't make much of an ethical difference.