Yes, let's force a woman to go through months of pregnancy and risk her life giving childbirth to a baby she doesn't want to have.I'll admit, I would choose to save the infant. But here is the reason why. In this scenario you have a guaranteed death of one of 2 "things". I have said before that if the mother's life in danger, then by all means, abort the fetus. But in the scenario of an abortion, both the mother and the infant have the potential to keep living.
Now in the example, there is a fetus and an infant, if I had to make that horrible decision, I would allow the infant to live, because the baby could feel pain, and even pro-choicers will call it sentient. If the fetus could feel pain, then that would make the decision much harder. But just because something cannot feel pain, does not mean it isn't alive.