From Newdonkey.com

Part of the full-human-life-begins-at-conception point of view is typically that "conception" occurs at the moment when an ovum is fertilized. Anything that deliberately interferes with live birth after that instant is an "abortion." Thus, most really hard-core right-to-lifers believe that birth control methods (including not only morning-after pills but IUDs) that in part or in full rely on preventing implantation of the fertilized ovum in the uterine wall are not "contraceptives," but "abortifacients" that are morally indistinguishable from a late-term abortion or, for that matter, infanticide. Never mind that this kind of "abortion" occurs naturally in a very high percentage of proto-pregnancies; ideology is ideology.