That does not mean that a situation outside those bounds might exist that makes it necessary.
"Outside those bounds"?
They are the "bounds" you described! You're the one who brought up life of the mother to defend childkilling:
What about a case where only the mother could live?
Within those "bounds," it is never necessary to stop delivering the baby in order to kill him.
If a situation arises where the best course of action is to end the pregnancy, you deliver the child. It is never necessary to stop delivering the child in order to kill her.
"Bounds."