"So by your logic"
Just a minute. Get one thing straight. This is not "my logic." This is a position that has been widely held throughout Western Civilization for a couple of thousand years. That's what you're arguing against; not just some faceless turkey on the internet.
"if continuing a pregancy would likely be fatal to a woman, she should be forced to do so anyway?"
Tendentiously phrased, wouldn't you say? "Forced," as though to say "Of course she would kill her baby to save herself."
So what's your answer?
For thousands of years an abortion wasn't possible without seriously sickening and likely killing the mother. Usual approach for barbarians was to strangle the child as it emerged. (Now we use scissors, I guess that's better.)