The fetal heart rate (FHR) is a fundamental tool for clinical monitoring, when investigating the wellbeing of the fetus. The detection of the QRS complex of the fetal electrocardiogram using the abdominal signal enables the non-invasive evaluation of the FHR. There are many clinical causes for FHR variability, but a slight variance indicates a good evolution of the pregnancy. The current study evaluates the RPA model for a 5-channels abdominal records (ADS), in order to study the chaotic dynamic model of the FHR and to reveal the correlations in the time-domain.