It’s also not at all a purely hypothetical situation. There have been at least three cases like this I can think of within the past 10 years in South America that attracted attention (Argentina and Brazil, can’t remember if the third was also in one of those or another country). In all three I believe the rapist was the girl’s father - not really a situation where she can report it. In two she was able to get an abortion, but in one she was forced to carry it to term and deliver by C-section (because normal delivery would have likely killed her, another example of how grotesque this is). [ETA: I see lastroth already linked to this one]
In the one in Brazil, the Catholic Church actively campaigned to block the girl (who was 9) from having an abortion, and afterward excommunicated the doctors and the mother - but not the rapist father, since he had confessed.