The role of ultrasound in the diagnosis and management of intrauterine growth retardation.
Ultrasonography has contributed greatly to our ability to diagnose and evaluate fetuses with IUGR. This tool has helped us begin to understand the pathophysiology of the spectrum of disorders we group as growth restriction. The heterogeneity of the syndrome contributes to our inability to find perfect sonographic diagnostic markers, but the information gained from ultrasound still far surpasses that available from other clinical methods. Sonographic estimated fetal weight seems to be the best parameter for diagnosing IUGR, although weight percentiles alone will lead to misdiagnosis or missed diagnosis in some cases. Umbilical artery velocimetry may be the best diagnostic tool in cases in which gestational age is unclear, but sensitivities are not adequate for general screening. Growth measured by change in abdominal circumference also shows promise for diagnosis of IUGR, but is dependent on serial examination. Doppler velocimetry has provided insight into the hemodynamic changes which occur with growth restriction, but findings are poorly predictive of outcome when used for screening. When end diastolic flow is absent or reversed, the incidence of adverse outcome can be high, but adverse outcome can occur without these findings and normal outcomes can occur despite them. The search for methods to improve assessment of fetal status and manage pregnancies with IUGR to maximize fetal outcome will continue.