But neither of these two arguments necessary lend themselves to the either/or options you've suggested. A person could feel that life is sacred and therefore oppose abortion in the case of rape, or under any circumstances whatsoever.* A person could feel that the woman is the decider and therefore support the right to abortion at all stages in the pregnancy, not just up until viability. And that's excluding the people whose views on the subject aren't based on concerns about life or choice anyway, but sexual control/morality, racial issues etc...
People are all over the place on abortion, I just don't think you can narrow it down to only two positions, basically.
*The anti-abortion movement in Ireland doesn't even support exceptions to save the woman's life... although this is based on a creative definition of "abortion" which excludes any procedure aimed at saving a pregnant woman's life.