Abortion isn't analogous to pulling the plug on someone on life support. It's analogous to sending someone on life support on a guillotine. The fetus is violently killed during the process.

Analogies are dumb when it comes to abortion.

The point is if you decide a mother has a right to cut the umbilical at any time, the fetus will die regardless during most phases of pregnancy (the ones where abortion is legal in the US.) So now you get to decide given death is a certainty, what is the proper act. I could be persuaded the current mechanisms are the wrong choice. Would you propose to just cut the cord and let the fetus starve in the womb?

I'm pro-choice, but I imagine that a lot of pro lifers would be less horrified by abortion if that were the case. My point is that the body autonomy argument is in bad faith and simply meant to spread propaganda that conservatives are misogynists. Given the violent nature of abortion, one can only conclude that people think it's ethical because they don't consider the fetus a human life.

I believe you are right than many pro-choice advocates have lost the plot and think it’s about the right to choose to kill vs choose to cut, or that right comes from a lack of personhood.

However, that aside, my point is that once you take death as inevitable, then the mechanism to do may fall to minimizing suffering. And so, it stands to reason that a procedure which a) doesn’t result in long, perhaps painful starvation and b) doesn’t put the mother at risk by having a dead fetus inside of her are worthy considerations. I do think that you are right to think that the violence of current procedures, while perhaps ethical due to minimization of suffering, may be contributing to moral confusion about the right to cut vs right to kill or the dehumanization of the fetus. I do fear that as this moral confusion winds it’s way upward, the rights to abortion may expand beyond viability, which to me would flip my position on where I stand with regards to maintaining the legal status quo vs reversing it. I support Roe v Wade but would not support a law which gave a mother discretion to terminate past viability.

Does this imply then that, let's say a mother was in a position where breastfeeding her child was the only way the child would survive (in the wilderness for some reason, for example), that she should be acquitted if she refused to do so and the child died? The baby needed to be hooked on her body to survive.

A mother has a right to refuse to breastfeed but that doesn’t imply that she would be innocent of parental negligence for failing to find an alternative way to take care of the child. Once a child is born to legal guardians there are minimum standards for caregivers.

IANAL, but the word you are looking for is intent:

https://en.wikipedia.org/wiki/Intention_(criminal_law)

If it's clear the mother went to the woods to create this environment to kill the child, then a state could consider prosecuting.

If there was a plane crash and it was clear that the mother was distraught and this was a side effect of the crash, I don't think most states with prosecute, but again, depends on the state.