In the US, only 2% of all abortions are labeled as medically necessary to save the life of the mother and some fall into this category because the mother was......d e p r e s s e d.
That is what I have heard from medical professionals I know (specifically a registered nurse I know who works with pregnant women on a daily basis). In the modern world, abortion is essentially never necessary to save the mother's life.
That is why the abortion debate, in America at least, focuses on the health of the mother, not the life of the mother. Yes, mental health. Depression is grounds to murder a baby. Wow.
This is, again, missing the point - we're not able to say with 100% certainty that abortion is never necessary to save the mother's life. We can say "essentially never necessary," but not "never." So in the rare, very rare, or extremely quite very certainly supremely rare case that it is necessary, it will be handled differently than in the other cases.
We're not able to say a lot of things with 100% certainty. We should not base our morals on hypothetical cases that may or may not happen at all, and if they do, it is so rare it's statistically not worth talking about. Because when you do that, inevitably other things start being justified. "If that extreme circumstance is okay, why not this slightly less extreme circumstance? Why not this one? Or this one?"
Unfortunately our fallen nature causes us to push the envelope in search for validation. Meanwhile, the Church does not fiddle about with things, and says abortion is a sin, and leaves it at that.
And for what it's worth, I personally don't think abortion is ever
justified, even if life is at stake. Ending one life to prolong another, especially in such a calculated field as medicine, strikes me as very wrong. And I don't think artificial fertilization that results in discarding embryos is right either. I say this having cousins who came from such techniques. I love them like they are my brothers, yet I despise the methods that caused them to be, and I am sad that they had other brothers and sisters who were so prematurely sent back to God.
It is all a devaluing of human life. All of it. It seems that as soon as humans are able to understand—and then control—something, we lose our awe and respect for it.
[edit to add]
All of this is precisely why so many Fathers tell us not to become too familiar with worldly people. St John Chrysostom went so far as to trash most every form of entertainment known in his day (and he was not talking to monks, he was talking to regular people). Because when we become familiar with something, we sympathize with it. When that "something" is sinful, we become sympathetic. We see their point of view. We understand where they are coming from. Our own morals start to slip, and before long we have very much become "of the world".
And even worse: worldly people see Christians empathizing with, and understanding, and accepting what they do. That leads them astray, because they think we are not aiming for anything higher than they are. How will we feel on Judgment Day if our eyes are opened to all the people who we Christians led into Hell by our inaction and silent assent, if not outright misdirection?