Prognostic components of computerized fetal biophysical testing

Fetal biophysical testing with arbitrary scores for fetal heart rate (FHR), breathing movements, body movements, tone, and amniotic fluid volume has not proved to be highly sensitive or significantly better than FHR testing alone. Using a computerized analysis system for simultaneously acquired biophysical variables, we studied 200 high-risk fetuses near term. The dynamic parameters obtained for each fetus were compared with established nomograms, and overall test results correlated with the presence or absence of perinatal mortality, fetal distress, a 5-minute Apgar score <7, and intrauterine growth retardation for those delivered within 7 days of the last test. A test was considered abnormal if two or more parameters fell more than 2 standard deviations from the population mean. A decreased incidence of fetal body movements, amniotic fluid volume, and frequency of FHR acceleration were the most common individual test abnormalities. Test sensitivity (86%), specificity (89%), positive predictive value (75%), and negative predictive value (93%) exceeded those of the “standard” scoring approach and correctly identified all fetuses with malformation, perinatal death, and 19 of 22 fetuses with intrauterine growth retardation.