The USCCB Committee on Doctrine has issued a clarification on the difference between direct abortion and a medical procedure that has the unintended "double effect" of removing a developing fetus from the womb. (NCR has the statement immediately following its coverage.) Although the committee doesn't explicitly address the case in Phoenix, in which an 11-week preganancy was terminated due to the mother's deteriorating condition, the statement seems to confirm Bishop Thomas Olmsted's judgment that the procedure was a "direct abortion," and so immoral. He also judged Mercy Sister Margaret Mary McBride excommunicated because she signed off on the abortion as a member of the hospital ethics committee.
The bishops argue that it is permissible to remove a diseased organ, such as a cancerous uterus, even if it has the unintended consequence of killing the fetus; in the Phoenix case, the pregnancy was causing dangerously high blood pressure that the medical staff judged would lead to the mother's death. Removing the fetus to remedy that situation, however, was judged an immoral means to an end.
I have seen some moralists argue that the placenta was the malfunctioning organ here, but it was actually functioning properly; the hormones it was secreting were leading to the high blood pressure.
Other moralists have said that the problem lies with the principle of double effect; it doesn't apply here. Some have argued that the principle of killing in self-defense applies, even though the fetus is innocent. It would be morally permissible to kill an schizophrenic or altered person who was attacking you, even though they too would be innocent.
It's a difficult case, however, and difficult cases make bad law. I'm not sure this is the one anybody should be excommunicated over.
