Quandry

I will start posting new, awesome stuff soon. But first, would like to ask a question that's bugging me right now:
How, philisophically, can you be pro-natural birth, anti-death penatly and still "pro-choice?" I'm pretty much left-wing when it comes to politics, but am really confused as to how abortion rights fit almost necessarially into the liberal point-of-view. I just came from a presentation about the virtues of natural death and natural birth and can't think of anything that combines birth and death in a more unnatural way than abortion.

Am I missing something huge here? It seems like I must be.