My wife, hands down, with great sorrow and reluctance at sacrificing a child. And I am the father of three children and mercifully never will have to make this sort of decision. We are just too damn old for another pregnancy.
At the time in my life when we were beginning our family, learning of her pregnancy, watching her and her fetus evolve, dealing with the joy of impending birth, I would still have to favor her in view of these horrible choices. She is the love of my life and (hopefully) I of hers and being responsible for her permanent absence in my life by choosing a fetus over her would make my days unlivable and dealing with an infant in those circumstances would be unthinkable.
I am no expert on even my own religion, but in Judaism we are taught that what is paramount is saving a life. There is no rule, law, commandment, holiday, Sabbath, whatever, than can not and should not be broken in order to save a life. Given the circumstances stated by the original poster, the life belongs to my wife and the child she might be carrying is not born yet. I don’t want to argue about unborn children or other descriptions of a potential child still in the womb, I am just speaking from my own perspective what I have been led to believe in my upbringing.
As some posters have said, it depends on circumstances, and if forced to make this decision under extreme pressure and in great haste, I might do something else. But with the freedom of time to contemplate that we get on Fluther, that’s what I would do.
SRM