Isn't it, though?

By that same logic, I can walk into a hospital, go to someone on life support who can't currently "survive on their own", and unplug their systems, thus "withdrawing the support they require to live". If they die, is it really any different from killing them any other way?

To make the analogy even more accurate, let's say you are in a coma and will come out of it in 9 months. You can't survive without support now, but we know for a fact that you will come out of the coma after the 9 months have passed and will then be able to do so. Is it fine for me to shut down your life support half way through?

Good point. To make it closer to leetcrew's point, we could further imagine that while I'm lying in bed in the 9-month coma, you're the one paying my medical bills, and it's almost driving you bankrupt. Or: you need a heart transplant or you will die, and my heart is the only viable candidate.

to clarify, by "withdrawing support" I meant withdrawing support that you personally are providing, not just running around yanking ladders out from under people.

in the specific case of pregnancy, the support is given at significant personal cost and risk, which is not captured in either of your analogies.

Fair enough, let's assume that in the previous analogy I am actually the parent footing the hospital bill. If I know for certain that you are going to recover, and I can afford it, but decide to let you die anyway, is that really significantly better?

However, I do acknowledge that there are exceptional circumstances, such as the birth posing a health risk to the mother, both mother and child being likely to die if delivery is attempted, etc. That would be the case of "not being able to afford it" in my analogy, or the significant personal risk you mention (at least I assume that's what you mean, as normal pregnancy is nowhere near a significant risk, with the current maternal death rate being 1 in 10,000). In those cases, I'd be willing to agree with you.