Final answer:
Fetal viability refers to the point at which a fetus can survive outside the uterus, with over 90% survival rate after 26 weeks of gestation and necessary medical care. Intrauterine growth restriction (IUGR) can affect fetal growth, with placental insufficiency being a common cause. Low birth weight increases the risk of mortality shortly after birth.
Step-by-step explanation:
Fetal viability refers to the point in fetal development at which the fetus is likely to be able to survive outside the uterus. The chances of survival are much better after 26 weeks of gestation, with more than 90 percent of babies surviving if they receive necessary medical care. Babies born earlier than 26 weeks have a lower chance of survival due to inadequately developed respiratory and nervous systems.
Fetal growth generally increases linearly during the fetal stage until the last week or two before birth. Intrauterine growth restriction (IUGR), which is a deficit in fetal growth, may occur due to various factors, with placental insufficiency being the leading cause. The average weight of a full-term infant at birth is around 3.4 kg (7.5 lb), and low birth weight is defined as less than 2.5 kg (5.5 lb). Low birth weight increases the risk of mortality shortly after birth.