Catholic teaching has always been that each life is inviolable and neither may be directly killed to save the other. The principle that the life of both mother and child is sacred and inviolable is a life-saving principle. In the long run it saves many lives that might have been lost. Doctors who know they have no right to sacrifice either life are much more likely to find means of preserving both lives than are doctors who readily employ direct therapeutic abortion. Therapeutic abortion is a deliberate destruction of innocent life, morally evil and scientifically unjustified.
Therapeutic abortion is legalized murder.
It is not the case of attaining a good effect by means of the bad, because the mother's life is saved, not by the death of the fetus, but by the removal of the pathological condition.