THE MOTHER'S LIFE
The so-called "life of the mother" exception for abortion is unnecessary and dangerous. To begin with, there are no situations where abortion, defined as the direct and intentional killing of an unborn child, is medically necessary to save the life of the mother.
...

Medical operations such as the removal of a cancerous uterus or the removal of an ectopic pregnancy are moral even under Catholic teaching and are not considered abortions. If a pregnant woman has a cancerous uterus that imminently threatens her life, then the uterus may be removed even though such removal results in the death of the unborn child. Similarly, when a fertilized ovum lodges in the fallopian tube and grows there, the damaged portion of the tube containing the baby may be removed where it is clearly necessary to save the mother's life. Such operations are justified by the "principle of double effect," because the death of the child is an unintended effect of an operation independently justified to save the mother's life. They do not involve the intentional and willful destruction of an unborn child.

Legally, such operations are not considered abortions. The removal of such conditions has never been prosecuted in this country, even when the mother's life was not immediately threatened. There is, therefore, no need to provide a specific exception for such cases in a statute or constitutional amendment prohibiting abortion. Moreover, an explicit exception for the life of the mother is dangerous. One should never attempt to codify in law the importance of one innocent human life over and above another. Physicians must make their best effort to save both patients, giving equal care to mother and child. They should never be given a license to intentionally kill either of them.

Finally, many abortionists believe that the very condition of pregnancy itself is a life threatening condition. Consequently, a "life of the mother" exception can become a massive statutory loophole through which to drive abortion on demand.

Once pro-lifers say there can be a "good reason" to kill a preborn baby, the foundation of the pro-life movement crumbles. The argument is lost. Either the preborn child is a person, or the child is not a person. Since the preborn child is a person, there can be no exceptions for abortion.