Rashi Sanhedrin 72 b says דכל זמן שלא יצא לאויר העולם לאו נפש הוא וניתן להורגו ולהציל את אמו אבל יצא ראשו אין נוגעים בו להורגו דהוה ליה כילוד
Before a baby is born (most of it or most of its head) its not a nefesh, after birth it is.
So can I just make an abortion for no reason? Consensual?
Or perhaps just maybe it means, it’s not a separate soul as it requires its mother to keep it alive so if it is endangering the mother you can kill it, for it is really killing itself anyway?