[I don't think most people would consider suicide to be "murder". That would be like saying "masturbation is rape". Forcing women to give birth would be analogous to forcing people to donate blood and organs to save lives.]

Both your analogies are out of context. Suicide is not murder. Murder is when someone kills someone else.
People choose to donate organs and blood to help others. Killing an unborn child takes away everything from that unborn human being. It has no way to defend itself. Again, taking the moral highground isn't easy, especially in cases where things like rape is involved. But do you really think such cases justify murder?
That's cold man. Nazi's thought of those kind of solutions 60 years ago and they got beaten down by the rest of the world.