What does the term "viability" refer to in the context of pregnancy?

The term "viability" in the context of pregnancy specifically refers to the fetus's ability to survive outside the womb. This concept is crucial in obstetrics, as it indicates a stage of fetal development when there is a significant chance of survival if the fetus is born prematurely, typically around 24 weeks of gestation, depending on various factors such as healthcare availability and the development of the fetus's organ systems.

This definition highlights the importance of gestational age and the physiological maturity of the fetus as determinants of whether it can thrive without the protective environment of the uterus. Other options discussed, such as the mother's readiness for childbirth or the fetus's heart rate stability, while important in their own right, do not define viability. Additionally, simply achieving full term does not directly relate to the independence of the fetus from maternal support for survival, which is the key aspect of viability.