your first friend sacrificed her life for her child, and your second may. That is part of "choice," too. I don't know if I'd be that Christ-like.
My second friend angers me, because she plans to abort when her life is in crisis - making it a sick mid-term abortion.
The first didn't do it out of Christ-like love, but a twisted sense of piety.
I'm with you - I couldn't look my sons in the eyes and tell them I'm going to die so they can have a baby brother or sister. I love them too much to put them last and hurt them so deeply. I would also expect them to grow up resenting me and what I stood for.