Recent advances in management of fetal growth restriction

Kim, Young Han; Kwak, Dong Wook

Abstract

Small-for-gestational-age (SGA) is associated with poor perinatal outcomes. The term SGA is descriptive and means that the fetal size and weight at birth are less than expected (in general, 10th percentile using standard curves for gestational age) regardless of the cause. It was estimated that about 50~70% of fetuses born weighing less than the 10th percentile for gestational age are constitutionally small, with fetal growth appropriate for parental size and ethnicity; these are usually associated with normal placental function and have a normal outcome. Fetal growth restriction (FGR) describes a decrease in the fetal growth rate that prevents an infant from obtaining the complete genetic growth potential. It is common with placental dysfunction occurring in about 3% of pregnancies despite advances in obstetric care. In human pregnancies, placental insufficiency is the leading cause of FGR and is usually due to poor utero-placental blood flow and placental infarcts. The reduction of placental supply of nutrients to the fetus has been associated with several adaptive changes taking place in both the placenta and fetus. Adaptive changes can be followed by pathology leading to fetal death, and therefore staging of the disease is fundamental to timing delivery. Thus, it is responsible for the obstetricians to distinguish SGA from intrauterine growth restriction, correct the causes if possible, and if not, accurately stage the disease progress so as to deliver at the most suitable time. In this review, the management of fetal growth restrictions is summarized based on the diagnosis, etiologic factors, antenatal surveillance, and their possible therapeutic approaches.