If one is religious, then the unborn are not innocent.
They are part of their god's plan, and when aborted, that is according to plan as well.
If they go un-aborted, given that they were "given life" by an omniscient and omnipotent creator, that creator had already predetermined at the time they "gave them life" exactly how their entire life would go, down to the smallest minutia. As such, they are not "innocent". You just personally don't know what atrocities they will commit in the future. But if you're religious then you have to believe that they are already predetermined to create them.
Kill the fetuses. Kill the prisoners. Hell, kill the prisoners using dead fetuses.... or vice versa.