Abortion is not killing. Otherwise, I would've been able to sue anyone who has done abortion.
Rape or sexual abuse victims would lead miserable life if it were not for abortion. And this is more important in the first place than considering whether we are ending a life or not. Just google, you'll find hundreds of points of how abortion is or is not killing.
If I get a needle stuck in my hand, I'll draw blood. I will 'kill' some cells of my body. Does this make me a killer? A foetus is not a human unless it is given birth. Its just a collection of cells, like that in my hand. And 'killing' cells is not a problem unless its killing a human.