Intrauterine growth restriction (IUGR), also called fetal growth restriction (FGR), occurs when the fetus does not achieve its genetically determined growth potential. It is most commonly defined as an estimated fetal weight below the 10th percentile for gestational age on ultrasound biometry. IUGR is associated with placental insufficiency, maternal hypertension, congenital infection, and fetal anomalies. Management involves serial ultrasound growth assessments and umbilical artery Doppler surveillance, with timing of delivery based on the severity of Doppler abnormalities.