if I were to attempt to do to Jane Doe what pregnancy and childbirth do to a woman, she would be legally justified in killing me to prevent it.That would be the rapist, not an innocent baby.
How would that not be the baby?
You have a great point. At 4 months in an adult woman, there is some outward physical change, but not a significant one. As it proceeds, organs move, the hips change shape, and nothing works quite the way it did before. In a 9 year old, the changes wrought would be phenomenal, and likely life threatening and visible to all(except for a committee of politically appointed reviewing hacks makes a tepid recommendation to the church and government).
Don't kid yourself - for the true believers, once someone is raped, there should be no D&Cs as part of the rape kit, no RU-486, nothing, because that might disturb the pregnancy that might be taking place.