 Introduction/Background Fetal growth restriction (FGR) is an important complication of pregnancy and is associated with significant risks of perinatal morbidity and mortality. A small-for-gestational-age (SGA) fetus is defined as a fetus whose estimated fetal weight (EFW) is below the 10th percentile for gestational age [1,2]. FGR implies an SGA fetus that has not reached its growth potential as measured by EFW. Although some SGA fetuses are constitutionally small and not at risk for perinatal morbidity and mortality [3], others are affected by a variety of maternal or placental conditions that lead to uteroplacental insufficiency and potential adverse outcomes, such as neurodevelopmental delay [4]. Given the difficulty in differentiating fetuses who are constitutionally SGA from those with FGR, it is typical for all fetuses with an EFW below the 10th percentile to be treated comparably. Finally, some fetuses may have an EFW at or above the 10th percentile but may also be at risk for adverse outcomes because of their suboptimal rate of growth [5,6]. The diagnosis of FGR is based upon an accurate assessment of gestational age. If gestational age is uncertain, then repeat evaluation to ensure appropriate growth velocity is recommended. Many different fetal biometric growth curves exist, and it is preferable to use the growth curve that most approximates the population being studied. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through society representation on expert panels. Participation by representatives from collaborating societies on the expert panel does not necessarily imply individual or society endorsement of the final document. Reprint requests to: publications@acr.org
Growth Disturbances Risk of Fetal Growth Restriction.  Introduction/Background Fetal growth restriction (FGR) is an important complication of pregnancy and is associated with significant risks of perinatal morbidity and mortality. A small-for-gestational-age (SGA) fetus is defined as a fetus whose estimated fetal weight (EFW) is below the 10th percentile for gestational age [1,2]. FGR implies an SGA fetus that has not reached its growth potential as measured by EFW. Although some SGA fetuses are constitutionally small and not at risk for perinatal morbidity and mortality [3], others are affected by a variety of maternal or placental conditions that lead to uteroplacental insufficiency and potential adverse outcomes, such as neurodevelopmental delay [4]. Given the difficulty in differentiating fetuses who are constitutionally SGA from those with FGR, it is typical for all fetuses with an EFW below the 10th percentile to be treated comparably. Finally, some fetuses may have an EFW at or above the 10th percentile but may also be at risk for adverse outcomes because of their suboptimal rate of growth [5,6]. The diagnosis of FGR is based upon an accurate assessment of gestational age. If gestational age is uncertain, then repeat evaluation to ensure appropriate growth velocity is recommended. Many different fetal biometric growth curves exist, and it is preferable to use the growth curve that most approximates the population being studied. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through society representation on expert panels. Participation by representatives from collaborating societies on the expert panel does not necessarily imply individual or society endorsement of the final document. Reprint requests to: publications@acr.org