Well.

Most people are not going to rally behind the idea of ending actual life. Most pro-choice camp members consider abortion permissible because it occurs before life begins (and the debate over when that is rages on!), and most pro-lifers oppose abortion because they believe life has begun and it is being ended, which is murder (a colorful word they like to throw around in captions beneath photographs of mutilated fetuses).

It's a harder argument to win if you say that a woman's right to convenience is greater than the right of her child to live. Again, we wouldn't feel comfortable ending the lives of children who have already been born but couldn't breathe alone, for example. Or even healthy children who have been born. It wouldn't be okay, because that's a life and to end it would be murder, which is the most vile act we can commit against one another. If you truly believe that life begins in that same manner and on that same level at conception, I can understand why you'd vehemently oppose abortion. I think you'd be wrong about that definition of life, however.