if you believe that abortion is the murder of a living human being, then it is not logically consistent that it is ok to murder that human merely because a crime was committed against it's mother or because it's mother may be physically inconvenienced or compromised by carrying it. the health of the mother exemption is not inconsistent and would still allow remedy if a health complication developed.
i wonder how far away it is from it being medically feasible to harvest an embryo and implant it in a surrogate in the case of rape? could it be done now, if there was demand?