COMPUTERIZED ANALYSIS OF FETAL HEART-RATE IN POSTTERM PREGNANCY

Objective: To verify the possibility that computerized interpretation of fetal heart rate in postdate pregnancy could increase the sensitivi ty of the other methods used in the identification of fetuses at risk for fetal distress in subsequent labor. Methods: Computerized cardioto cography by means of a '2CTG' system was utilized in a longitudinal st udy of 104 carefully selected, low-risk, postdate patients. Patients w ith gestational hypertension, intrauterine fetal growth retardation, s evere oligohydramnios, increased umbilical resistance, and sporadic va riable or late decelerations were excluded from the longitudinal trial to avoid the influence that preexisting factors could have on the evo lution of fetal heart rate recordings. Computerized results were not a vailable for clinical decision. A comparison on visual and computerize d interpretation of the recordings was made retrospectively without an y knowledge of the clinical outcome. Results: A significant increase i n the level of the basal frequency and a reduction in the variability, using the Interval Index (P < 0.05), were found in the group subjecte d to acute fetal distress during labor. The comparative evaluation of the same tracings using visual and computerized readings showed an inc reased sensitivity of the computerized reading (75 vs 25) of the posit ive predictive value (43 vs 17) and of the Kappa Index (36 vs 7). Conc lusions: Although cardiotocography still has a low sensitivity and a h igh specificity, the application of computerized interpretation togeth er with the evaluation of the other biophysical variables can increase the identification of subjects in postdate pregnancy who will risk ac ute fetal distress during labor.