FHRV assessment by means of symbolic dynamics

The foetal heart rate variability is one of the most important parameters to monitor the health of the foetus. There are so many studies, both in time and frequency domain, which analyze the foetal heart rate variability and showed its significant diagnostic value. However, these studies have shown some limitations in highlighting some of the dynamics potentially relevant in controlling of heart rate. Therefore, methods of non-linear analysis have obtained a growing interest to analyze the chaotic nature of heart activity and they have already been successfully used in adults. As for foetal monitoring, much less works are available. Recently, symbolic dynamics has been used to quantify the regularity of foetal heart rate, showing that its use can lead to a more complete and thorough understanding of normal physiological development of the foetus. In this work, we applied symbolic dynamics to analyze foetal heart rate variability in healthy foetuses at the end of a normal pregnancy. The results confirmed the potential of this method in emphasizing the differences between signals characterized by greater or lesser variability.