Fetal viability

Fetal viability is the ability of a human fetus to survive outside the uterus.

Viability depends upon factors such as birth weight, gestational age, and the availability of advanced medical care. In low-income countries, more than 90% of extremely preterm newborns (less than 28 weeks gestational age) die due to a lack of said medical care; in high-income countries, the vast majority of these newborns survive.

Medical viability is generally considered to be between 23 and 24 weeks gestational age, meaning that these newborns have a < 50% chance of either dying or surviving with severe impairment if active care is instituted; this applies to most babies ≥ 24 weeks of gestation, and to some babies at 23 weeks of gestation with favourable risk factors.

As of 2022, the world record for the lowest gestational age newborn to survive is held by Curtis Zy-Keith Means, who was born on 5 July 2020 in the United States, at 21 weeks and 1 day gestational age, weighing 420 grams.