The problem here is that we're not talking about rapes in general. We're talking about unwanted pregnancies that occur as a result of rape. That is what you are going to have to deal with. Neither is prison time for the rapist. By your rationalization, we should not send the rapist to jail since that is not a solution for the act he committed.
All abortion does is destroy an innocent human life.
It does not reverse a rape from happening nor does it resolve the violation that women experience emotional or physically. It is a risky procedure in some instance that can endanger a woman's life. But abortion fails as a solution to rape-pregnancy for another reason. It many times adds one mental trauma to another. Its is hard enough for a women to deal with the absolute violation she experienced as a result of a rape.