Even if you swallow the argument that a fetus is a "person", you still have to temper the rights of the fetus who is a parasite on the mother, who is a living, breathing person with rights of her own, including "life, liberty, and the pursuit of happiness".

If a dead person can't be forced to give up organs without prior consent, a living woman should not be forced to provide life support (at a risk to her own life by the way) for a fetus. Just like I can't be forced to donate a kidney to another person, a woman should not be forced to donate blood, bone and full life support to a fetus.

IOTW, it's literally a matter of competing rights to life. Carrying a pregnancy to term is a mortal risk. Certain pregnancies will kill the mother if not ended, and the fetus will never be viable. Other times the fetus is already dead, but since the law doesn't actually consider the fetus a person, it can't be removed due to abortion bans, and the woman is forced to carry a dead parasite and risk fatal sepsis.

All of this should be left to the woman, her doctor, her circumstances and her conscience, not a bunch of old men in legislatures and courts.