More practically, it allows you to claim what Jimbo here is describing without any practical loss. At two weeks pregnant, you likely haven't even had sex yet. A pregnancy test might not be positive until week five or so, and there are only a couple of abortion clinics in conservative states, so you've potentially got a window of just a couple of days between finding that you need one and getting one. So a six week ban is more of a PR move than an actual thing that people believe in.