I say again: "The argument is then about whether she has the right to decide how and when the baby leaves her body at that stage in the pregnancy."
And if some people are saying that women can make that choice, "for any reason", then that includes just wanting to end the life of the unborn and not have them in the world.
The alternative is policing what women do with their own bodies in late-stage pregnancy and risking criminalising doctors for late-stage pregnancy terminations. I'm not comfortable with making a woman stay pregnant if she doesn't want to be, nor am I comfortable making a doctor have to worry about being arrested and charged because his/her patient wasn't quite sick enough to justify an abortion in the eyes of the law.
In the AIBU thread, I suggested that a woman in later pregnancy could be effectively imprisoned in a hospital in a foreign country because broken waters and preeclampsia would require blood pressure monitoring every two hours and render her unfit to fly home. That example isn't hypothetical, I'm describing what happened to one of my cousins.
If, unlike Dcousin, that woman were to say "I don't want to spend 12 weeks confined to a foreign hospital and then give birth in a foreign country, I want an abortion so that I can go home", should she be forced to stay pregnant?