Advances in the Application of Ultrasound for Evaluating Placental Function in Fetal Growth Restriction (FGR) Pregnancy

Placenta is a vital organ of a unique circulatory system that allows the exchange of nutrients between maternal and fetal circulations, supporting fetal growth during pregnancy. The placental nutrient transfer capacity is precisely modulated by the signals originating from the fetus, mother, and placenta itself, thereby ensuring appropriate regulation of fetal growth. However, the abnormality of any link in this process may lead to the failure of the regulation, and thus the placenta can no longer meet the fetal demand, causing fetal growth restriction (FGR). This review investigates the morphological and functional alterations in the regulation of placental growth and development, as well as the uteroplacental circulation in human pregnancies complicated by FGR. Additionally, it discusses the ultrasound application in the assessment of placental insufficiency.