Reb Eliezer.
I wasn’t aware that the סברא to be maikil is bc they say it a חבלה. Not רציחה. If indeed this is this סברא it is an untenable position.
A) the drosho from where it is assur is שפך דם האדם באדם.
The Torah clearly is calling this שפיכות דמים. Nu, so you will taana why does a husband get paid for חבלה? Not a particularly bothersome kashya. An eved who is killed also gives the owner a monetary compensation and there surely is no heter to kill an eved.
B) why do we need to come on to רודף when being mattir when the mothers life is in danger. The simple klal of פיקוח נפש דוחה כל התורה כולה would clearly apply to חבלה. Nor vus, it is רציחה which only has a heter through the unique vehicle of רודף.