What term is used to describe a fetus that can survive outside the uterus with medical intervention?

The term used to describe a fetus that can survive outside the uterus with medical intervention is "legally viable." This term refers to the stage of fetal development when the fetus has reached a point in gestation where it has a reasonable chance of survival if born, typically around 24 weeks, although this can vary based on advances in neonatal care.

This viability signifies not just physical development but also legal implications, as it often influences decisions regarding the status of the fetus in medical ethics and law. The viability of a fetus is determined by its ability to function and thrive outside the mother's womb, aided by healthcare resources.

The other terms mentioned do not accurately capture this specific concept. "Fully developed" may imply that the fetus is ready for birth without further medical assistance, while "mature fetus" refers to a stage closer to term, again assuming it can survive without intervention. "Postnatal" means occurring after birth and does not pertain to the fetal stage at all. Thus, "legally viable" is the most appropriate term in the context of fetal survival with medical support.