Actually (sadly), many well-educated religious people I know still think it's preferable to let someone die ("It's God's will") than to actively save their life by killing a fetus. And some of these people have become doctors, nurses, surgeons, all that. I mean, yeah, in an ideal world no doctor would stand by and let a woman die, but then, in an ideal world there would be no unplanned pregnancies, no rape, no murder, etc.
We live in reality, not a utopia, and that's why we need laws to protect pregnant women from this kind of ridiculousness. I mean, heck, I wouldn't abolish anti-burglary laws just because I assume everyone else is a decent person who won't break into my house and steal my stuff.