Investigation and management of the small for gestational age fetus

The desire to identify the small for gestational age fetus is due to its association with stillbirth and poorer neonatal outcomes. The difficulty lies in determining which of these babies are just constitutionally small and healthy and which are growth restricted fetuses that are at significant risk of poor outcomes. Fetal growth restriction is often mediated through placental disease and shares a similar aetiological pathway to preeclampsia. Placental malperfusion results in impaired nutrient and oxygen delivery to the fetus. Appropriate risk assessment in early pregnancy and monitoring with symphysis fundal height measurement or ultrasound scans is a crucial part of the screening pathway. There is no effective treatment for growth restriction, so management is based on close monitoring and early delivery. Fetal growth restriction has better defined monitoring and delivery timing guidelines whereas it is more unclear and variable for fetuses considered only to be small for gestational age.