Say for some strange reason you wanted to kill a baby. Don't argue that you wouldn't ever kill one, just say that you wanted to kill one for some reason.
In theory, you could get pregnant without anyone knowing. Then you could go live in a cave with enough food for 9 months in hiding. It is possible. Or maybe you could just pretend your fat or got an evil fat disease if your not up for living in a cave. Then when the baby is born, you could kill it.
There wouldn't be any record of the baby or anything, and no one would know about it because of the hiding for 9 months thing.
I bet this happens loads.
There should be some sort of government organisation that prevents this sort of nastieness. They could be called the FINDING PREGNANT BABY KILLERS in CAVES (SQUAD/TEAM/LEGION.)