> what other sentient entity is available for consultation?

Surely you don't mean what you imply there? Not being sentient or available for consultation don't justify harming a person. A mother absolutely has a moral responsibility not to cause lifelong harm to the sentient entity her baby will later become. You wouldn't say excess alcohol consumption during pregnancy is only up to the mother's decision about her own body when there are adults walking around with terrible lives because of fetal alcohol syndrome.