We're in the era of "#BelieveAllWomen" which means that if a woman claims to have been raped, everyone has to pretend to believe her. So what happens if a state bans abortion, but there's an exception for pregnancies that were caused by rape? Every woman who wants an abortion is going to claim, "I was raped" and they'll have to allow her to get the abortion.
Even if the new law says that she's required to present some evidence of having been raped, the evidence is going to end up being her uncorroborated testimony, which they'll have to accept as adequate proof, or else the whole system of female supremacy falls apart, because it's all about giving women the benefit of the doubt when they make claims of victimhood. As soon as women are required to submit some physical evidence such as bruises or whatever (which, by the way, can be caused by rough sex that a woman wanted), the whole house of cards will collapse.