Biblestudent,
I am probably one of the most ardent pro-lifers you will find, been very close to this issue for many years, and most of the pro-lifers I know all say in the rare case a mother's life is indeed actually "threatened," then it is considered self defense, she certainly has a right to her survival with our full support. But let's face it: today's medical tech has virtually removed this from the realm of reality.

And, let's not forget the threat of the abortion itself.
In the last seven years, four major epidemiological studies have shown that abortion is actually associated with HIGHER rates of death compared to childbirth. The most recent study of pregnancy-related deaths was published earlier this year in the American Journal of Obstetrics and Gynecology. That study, linking birth, death, and abortion records for the entire country of Finland over a thirteen year period, found that women who had abortions were three times more likely to die than women who gave birth:
http://www.afterabortion.org/news/DeathsReview.htm

"What happens if the life of the mother is medically threatened?"

"This question has to be answered with a question. Just ask someone who is pro-choice: What medical condition are you referring to? 99.99% of the responders will not have an answer. There is only one biological reason why the life of the mother could be threatened by a fetus. (Ectopic pregnancy). Most often it is discovered early. The procedure to safely render the medically threatened mother entails the removal of the fetus but in most cases the viability for life for the fetus was threatened at the moment the egg made its attachment. Challenge those who believe in choice to ask a doctor if they know of any medical cases when it has been necessary to abort the fetus because the mother’s life is threaded after 45 days into development. Again this is another false argument."
http://open.salon.com/content.php?cid=22797