The role of real-time scanning in antenatal fetal surveillance

Abstract

The additional value of real-time ultrasound scanning (RTBS) in antepartum assessment of fetal well-being was studied in 158 high-risk patients after a nonstress test (NST). Fetal breathing movements (FBM), fetal movements (FM), tonus (TON), and normal amniotic fluid volume (AFV) when present on RTBS were reliable signs of fetal well-being. These ultrasound markers of fetal well-being appeared to be as reliable indicators of good outcome as the reactive NST. Multiple indicators did not improve the accuracy of the prediction of normal outcome. All test results were normal in only about 50% of patients. In general, abnormal test results were poor indicators of poor outcome. Only when all parameters were abnormal were babies invariably affected. Five of six babies with major anomalies showed increased AFV, and seven of 13 growth-retarded or postmature babies demonstrated decreased AFV. The parameters obtained on RTBS appeared to be far more reliable than the contraction stress test (CST) in discriminating the truly abnormal fetus. Three babies with positive CST in this study had normal outcomes. These results, if confirmed in larger studies, suggest that RTBS after a nonreactive NST is an effective and potentially economical method of fetal assessment.