Anyone who would stand in the way of another making a decision about the future child who THEY will have to give birth to and THEY will have to raise should volunteer to take that child in themselves once it is born, no matter what their situation, and no matter what the baby is like. Because obviously that's what they think others should do (adoption really isn't the simple, guaranteed thing a lot of "pro-lifers" believe it is). Also, they should pay for any therapy or medical treatment that the mother in question might want or need as a result of the father being a relative, a rapist or both, or from any medical complications she might suffer as a result of the pregnancy.
...Oh wait, that's right. "Pro-lifers" seem only to care about non-sentient, non-sapient beings in the womb. Once they're thinking, feeling beings who can live biologically independently from their mothers, they don't count anymore.
Though I understand in this community why there would be a noticeable pro-life slant in some circles, I think that the quality of life the child will have after it is born must be considered. If a kid with a severe medical and mental condition would be born into a family that could care and provide for it, and wants it, great. More power to those people. But if that kid was going to be born into a situation where there were no resources to take care of them, where both parents would be working day and night just to put food on the table, an environment that would be hardly fit for even a "normal" child? It could even be said that choosing not to give birth to a child like that at such a time would be the more responsible option. Even forcing well-to-do (enough) parents with one parent who stayed home, or with enough money to hire a nanny, to have and take care of a child they don't want for petty reasons of the baby not being "perfect" is not necessarily a good thing - that child could very well grow up knowing that he or she is resented, and believing that he or she was a mistake. Said kid might even be abused, physically or psychologically. And the chances of a child with severe disabilities getting adopted is just about nothing. Ideally, people would consider all possibilities before taking action. However, as few people ever will plan ahead, it's unfair to condemn or prevent people for making a decision that will affect the quality of life for, at very least, two individuals, if not more, without knowing what their reasons are.
The best way to prevent (not all, but many) abortions is to make it more feasible to raise a child under any situations - and easier to prevent pregnancies, of course. However, that is a much harder, much costlier, and a lot less marketable solution, so it's a much less likely route for public figures to try and take.