It is not the case that abortion is always impermissible.
The United States Conference of Catholic Bishops issued a statement in 2001 entitled Ethical and Religious Directives for Catholic Health Care Services, Fourth Edition. In this they state: “Operations, treatments, and medications that have as their direct purpose the cure of a proportionately serious pathological condition of a pregnant woman are permitted when they cannot be safely postponed until the unborn child is viable, even if they will result in the death of the unborn child (no. 47).”
What is not permitted is so-called “direct abortion,” which has as its intended purpose terminating a pregnancy, as contrasted with “indirect abortion” in which the death of the fetus is not directly sought but is an indirect result of, for example, an attempt to save the life of the mother, as in terminating an ectopic pregnancy.
What is so disturbing in the posts in this thread is the desire to paint the hospital, the doctors, and the nun who is the focus of the bishops statement as not caring about the unborn child or being unaware of, or worse rejecting, Church teaching. There are far too many people, including not a few bishops, who sin against charity and show no regard for the truth (through unwarranted assumptions and a failure to fully understand through investigating the facts) in their defense of Church teaching. The fact is that in health care there are lots of situations that don’t fit into our neat categories. I’d be willing to bet that the ethics committee, the doctors, and the nun involved in this story agonized over this decision and attempted to follow Church teaching.