I'm not qualified to pass judgment on matters of Christian ethics, but perhaps someone out there can deliver a verified biblical point of view on a thought that occurred to me while I was reading something (I don't remember, or care, what the source was) about anti-abotion and its "holy" mission to save the unborn.
Wouldn't it be even more compassionate to allow women carrying unwelcome children to deliver them into the care of devote believers who would foster them kindly, rebuke them fiercely, and transform them into devout believers? All you have to do is undertake thereat mission of adopting every unwanted child. It might be a burden at first, until this sacred movement gets under way, but other true believers would have see the light of your conviction and take part in the mission. You could start a blessed earthly salvation.