from Catholic Cuture site:
catholicculture.org/culture/library/view.cfm?id=3362&CFID=10643201&CFTOKEN=26130755
"The Church was also, and at all times, concerned about the woman’s spiritual welfare. Since it regarded abortion as a grave sin, it believed that it posed a serious danger to the woman’s immortal soul. Naturally, it wanted to discourage women from having an abortion since it regarded this violation of the commandment to love one’s neighbor as a form of spiritual suicide.
Abortion Violates The Law Of Love
In the thirteenth century Thomas Aquinas dealt with the question of whether it is permissible to section the uterus of a pregnant woman if this is the only way to baptize the fetus that is in danger of dying. The argument in favor of doing this is that the eternal life of the fetus is more important than the temporal life of its mother. Aquinas refuses to allow this and quotes St. Paul (Rom. 3:8) who says: “We should not do evil that there may come good.” It is an impermissible evil, according to Aquinas, to impose direct physical harm on a pregnant woman (in all probability causing her death) even when the good that is intended—the eternal salvation of the fetus—might be construed in a particularly theological sense to be a greater good than continuing the temporal life of the mother.29 Aquinas does not believe that an unbaptized fetus is necessarily deprived of salvation; but the logic of his argument reveals his conviction that even if the fetus stood to suffer a greater loss than the loss of its mother’s temporal life, the mother’s right to be protected from assault remains inviolable.
The three-century theological discussion between 1450-1750 centered on whether a woman ever had a right to abort. The factor that sustained the discussion was a genuine and abiding concern that, in certain circumstances, continued pregnancy would endanger a woman’s health, marriage, or reputation. No exception was found that would permit direct abortion, however, because no exception could be found that did not logically extend to other exceptions that were not prudent to make or failed to uphold the principle that all innocent human life warrants equal protection. But the debate continued in an effort to protect the pregnant woman as much as possible without violating more general principles that protected everyone."
…
"The Church has always upheld the principle that all innocent human life is deserving of protection. In trying to find exceptions to the abortion prohibition in the interest of providing better care for the pregnant woman, the Church never treated one form of human life as more important than another. Pope Pius XII makes this point clear when he states:
Never and in no case has the Church taught that the life of the child must be preferred to that of the mother. It is erroneous to put the question with this alternative: either the life of the child or that of the mother. No, neither the life of the mother nor that of the child can be subjected to an act of direct suppression. In the one case as in the other, there can be but one obligation: to make every effort to save the lives of both, of the mother and the child.33"