Short fetal acoustic stimulation test for rapid antepartum assessment of fetal well-being

Short fetal acoustic stimulation test (FAST) was prospectively studied in 604 high risk pregnancies after 28 weeks of gestation. Fetal heart rates were recorded 3 minutes before and 5 minutes after fetal acoustic stimulation. The results of the tests performed within a week of delivery were compared with perinatal outcomes. Reactive response to short FAST occurred in 597 cases (98.8%) while nonreactive response was found in 7 cases (1.2%). Nine fetuses were considered poor outcomes. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of short FAST to predict poor fetal outcomes were 66.7, 99.8, 85.7, 99.5, and 99.3 per cent, respectively. Short FAST has high specificity, negative predictive value and accuracy for prediction of poor perinatal outcome. This rapid test should be used as a screening method for antepartum assessment of fetal well-being in a busy antenatal clinic.