Nah that was a SD straw man. You could base it off diagnostic codes if you wanted the certainty he was seeking, but I don't think that's the best route.
I've already expressed my preference ITT: (1) non-viable fetuses get no protection; (2) if a doctor determines that carrying a viable fetus to term would likely cause death or permanent disability to the mother BUT live birth via induction and/or c-section would mitigate that risk as well as abortion would, no abortion; (3) same as #2, except abortion is the only way to avoid the risk, abortion is allowed.
I personally would be pretty comfortable that "likely" causing "permanent disability" gives doctors sufficient wiggle room to use their judgment without providing carte blanche authority to perform late term abortions.
Obviously if you're in the "stay out of people's business" camp, no standard will be palatable. But if we are already ok with laws against child abuse (don't tell me how to discipline my own kids in my own house blah, blah, blah) I don't feel like it's much of a stretch to talk about treatment of babies who are capable of survival outside of the womb.