Personally, I'd take my chances and let the baby live and leave that decision up to God. I don't think it's our place to decide which human life should be snuffed and which should be saved. Those three children could also be deprived of their mother if the mother got into a car accident or something similar. Taking a child's life is never acceptable.
I would not fault a mother who decided that. On the other hand, I would not condemn a woman who decided not to give up her life for her unborn child, especially if she had other children. Even if morality would demand that the mother be willing to give up her life for her child, morality does not give anyone else right right to force that choice upon her.