Why does this matter? The Government is precluded from compelling a woman to carry to term against her will whether or not the fetus is a person, and all that matters is what The Government's has the power to regulate.
BTW your reasoning fails, because a newborn can breathe on its own, vacate itself, and in the presence of nutrition, consume that nutrition.
In utero, you coud oxygenate the amniotic fluid all you want and the fetus would not be able to breathe nor vacate itself, ane even if the amniotic fluid provided nutrition it would not be able to consume that.