CLASSIFICATION AND MANAGEMENT OF GROWTH RESTRICTED FETUSES

Abstract

Despite a plethora of publications existing in the literature, there is still confusion about the definition and management of intrauterine growth-restricted fetuses. Fetal growth restriction (FGR) is defined by the American College of Obstetricians and Gynecologists as estimated fetal weight (EFW) less than that expected for gestational age. Clinically this is applied when the EFW is less than the 10th percentile because perinatal morbidity and mortality is increased in low-birth weight infants. Other investigators have proposed and used a variety of fetal definitions: a fetus with an estimated weight < 2SD (standard deviation) from the mean, the 3rd 5th or 15th percentile and an abdominal circumference 2 SD below the mean. Because of the different definitions, it is understandable why different information has been obtained in growth restricted fetuses and why different management schemes have been proposed. A second source of confusion in FGR lies in the fundamental misunderstanding that all growth restricted fetuses are the same, and all will progress to cardiovascular failure following a similar time frame. We believe that in FGR, 2 concepts are important: the first is to detect those growth restricted fetuses at risk for adverse perinatal outcome; the second is to optimize the timing of delivery for these fetuses.