Abstract
To study the utility of fetal heart rate (FHR) monitoring and actocardiogram for fetal diagnosis and the classification of fetal behavioral states, a comparison of the techniques and their results is undertaken. FHR analysis is straightforwardly applied in the criteria for fetal behavioral states, which are classified by FHR and movements of the fetal body, extremities and eyes, and obtained by one cardiotocogram and two real-time scanners. The actocardiogram records both FHR and fetal movement signals, where fetal gross movements, breathing and hiccuping are revealed but no eye movement. It is useful in the exclusion of a false-positive, non-reactive non-stress test, physiological sinusoidal FHR and false perception of hiccuping, and also detects fetal movement or its loss in pathologic cases. Fetal behavioral states 1F, 2F and 4F are recognized by the actocardiogram alone, but 3F is not identified unless eye movement is detected. It is simpler to classify all behavioral states by the actocardiogram and one real-time scanner than by the original technique. The actocardiogram alone, however, can identify 3F, if quantitative values of variability and acceleration are provided in 1F and 3F. Simple actocardiographic active and resting fetal states are useful not only to exclude false FHR diagnosis, but also to study complete fetal functional development at 37 weeks or more of gestation. Computer processing of electrical signals makes it possible to analyze cross-correlation of FHR and fetal movement, and automatically to detect fetal active and resting states, fetal breathing and hiccuping. It is concluded that the actocardiogram is studied by simpler parameters than the multiple ones of fetal behavioral states, and is useful for the analyses of FHR and fetal behavior.