Information Theory and Fetal Heart Rate Variability Analysis

The chapter describes fundamental concepts of Information Theory and Feature Extraction for the analysis of Fetal Heart Rate Variability (FHRV). In particular, the first part of the chapter reports definitions of Entropy and Entropy Rate, along with an introduction of practical algorithms commonly leveraged to characterize the fetal well-being during pregnancy or labor, such as Approximate Entropy, Sample Entropy, and the newly formalized Bubble Entropy. The second part of the chapter is dedicated to a technique called Phase-Rectified Signal Averaging (PRSA) and three PRSA-based features namely, Acceleration Capacity, Deceleration Capacity, and Deceleration Reserve, applied in the context of FHRV analysis. Given the relevance of PRSA in this scientific domain, both theoretical and practical aspects of PRSA and its derived features are discussed.