Every person alive who has not committed suicide is pro-life. Those who have not committed murder are also pro-life.
The thing with murder is that there's enough fear of the punishment, which can be death, that not many people are willing to do it. Factor in religious teachings / indoctrination. There are protections against us each being murdered.
But, not so for the little fetus, which is defenseless. Its only protection is its mother, and if you can get into the mother's mind and convince her to do the deed, then its done.
Whether the law permits or forbids abortions, some will still occur, just as with other crimes or prohibited acts.
But when the law does not afford the fetus the same protection as all other persons, the net result is that the value of all life, even adults, is decreased.
The government has laws against harming the habitat of spotted salamanders, that are more stringent than those for the fetus, which makes salamanders of more value than humans.
Lawful abortion, although only seemingly applicable to the unborn, actually devalues all human life.
Nature provides natural substances, "abortifacients", that cause abortion. Personally I view these as being safer than an abortion performed by one licensed to do abortions, because the woman is sometimes harmed internally from ever being able to have children, whereas the abortifacients don't cause this.
The role of government must be to protect the weak from the strong. The strong, by definition, need no protection. What could be weaker and more defenseless than a fetus ?
Public policy should be against abortion. Yes it would still occur. But the message having abortion legal sends, is one of low moral character. Such a policy demoralizes the entire society, and creates division. Perhaps that was its intent.
Of course, it all boils down to behavior. Many women have never had an abortion, because they controlled themselves and only bedded down with a man they loved or would marry or were married to. Its the irresponsible behavior that is the issue. Women need stable strong men, so that if they get pregnant, they can count on him to stand by her side and give her the attention and support she needs. That's the basis of marriage, giving the woman reassurance that its "till death do us part" so a moral guy can't run out on her. When the population contains fewer of such men, the reproductive urge, remaining the same, necessarily means there will be un-wanted offspring. Unwanted at the time, at least. But there are so many successful people that were unwanted, and if you use the want of a young female as a sole criteria in determining whether a person should live or die, I think that's the wrong criteria. Gerry Ford and Alexander Hamilton come immediately to mind, surely there are thousands of other talented men and women who weren't wanted at some point. Why are people so ego-centric ? Szent-gyorgyi wrote about that once in The Crazy Ape.