The act, like suicide or self mayhem, was classically held to be self punishing because the natural bond between mother and gestated child was so close. And so penalties of law were light or nil.
I am almost amused, if it were not for being saddened, at the attempts to address these issues de novo, as though we had no history.
Remorseless women who kill multiple babies laugh at this naive white knight delusion about female psychology. Women with healthy maternal feelings aren't the ones who will be seeking out abortions if they're outlawed. The malefactors will need more disincentives than their own consciences, which are self evidently defective. Therefore they must be punished.