The abortion would be more analogous to her refusing to care for the baby and him/her dying as a result of the neglect.
Except normally speaking caring for a baby doesn’t involve risk to the mother’s life, pregnancy does, so your analogy isn’t perfect either, but in fairness I doubt any analogy would be a perfect stand in for such a unique human experience.
That said, if the needs of the newborn weren’t so great we wouldn’t be satisfied with letting nature take its course. If the child was born needing a minor corrective surgery, that carried little risk, a decent to high chance of success, and was financially viable, would you accept a parent refusing them that care as being morally right simply because not performing the intervention was the same as letting nature take its course? I think many would find fault with that, so we can’t simply appeal to nature as being the arbiter here. Nature aborts a large number of pregnancies.
I guess my objection is best summed up by your parenthetical though. “Assuming nothing goes wrong.” In a country where a majority of people and the laws supported pro-life stances, how much risk does a pregnant woman need to assume? If there’s 90% chance of complications which could lead to the death of the mother does she have to carry that pregnancy and take the risk? She did, after all, put herself in that situation unless she was raped, as you pointed out. If not, 60%? 30? 10? What if it’s unlikely she dies but likely she suffers a stroke or something debilitating like that. Must a woman with a 90% chance of having a debilitating stroke carry to term? 60? 30? 10? If there’s a number where it’s okay, does that mean abortions were more moral in the past when the risks were more likely? Is a woman in a developing country with less access to modern medicine more morally right to abort than one where the risks can be better managed?
I know I’m throwing a lot out here but I feel like these are natural questions that should follow arguments for pro-life oriented laws and yet I don’t hear them discussed. I’d like to see something more formally written that could potentially become law and more thoroughly expounds on what would and would not be permissible. I would think pro-life proponents would want to see the same, as drafting legislation is an important step towards implementing it.