Development and application of a simple expert system for the interpretation of the antepartum fetal heart rate tracings (version 88/2.29)

A simple expert system is developed for the interpretation of antepartum fetal heart rate tracings. The perinatal expert chose to use the phrase 'Fetal Reserve' to describe what the cardiotocogram is indirectly measuring. Our analysis program gives numerical values to each CTG such as 5, 4, 3, 2.5, 2 and 1 corresponding to the fetal reserve conditions of good, satisfactory, probably satisfactory with uncertainity, borderline, decreased, and critical respectively. This study consists of 33 normal pregnancies with normal outcome. Each patient is followed by our computerized system biweekly from the 28th to the 38th gestational week and weekly there after. The expert system's decision for 28th, 30th, 32th, 34th, 36th, 38th, 39th and 40th gestational weeks were 3.3 ± 1.0, 3.8 ± 0.7, 3.8 ± 1.0, 4.1 ± 0.9, 4.1 ± 0.7, 3.6 ± 1.0, 4.2 ± 1.0, 3.8 ± 0.9 and 3.4 ± 1.2, respectively. In this study, we have used confusion matrix to determine the normal, security, and danger zones according to the perinatal expert and the expert system and the discriminatory power of the system is found to be highly significant statistically (Q = 221). We also showed that the passive test (non-stress test) in normal pregnancies has demonstrated false positive results in 4.2 and 9.3% of the cases according to the evaluations of the perinatal expert and the expert system, respectively.