Final answer:
Intrauterine growth restriction (IUGR) is the abnormally slow growth of a fetus, which can be due to various factors. Amniotic fluid levels can also be indicators of potential issues. Ultrasound imaging is preferred for studying fetal growth and development.
Step-by-step explanation:
Intrauterine growth restriction (IUGR) refers to the abnormally slow growth of a fetus, which can occur due to maternal, fetal, or placental factors. Too little amniotic fluid (oligohydramnios) or too much amniotic fluid (polyhydramnios or hydramnios) can be indicators of problems during pregnancy. The use of ultrasound imaging is the technique of choice for studying fetal growth and development because it allows for non-invasive visualization of the fetus and its development.