QRS triggered averaging for superimposed PPG separation

Abstract

The current technology of electronic fetal heart rate monitoring shows inaccurate nonreassuring fetus status during intrapartum period. Recently, the fetal pulse oximetry has been introduced as an alternative technique to assess fetal oxygen status. However, the drawback of non-invasively recorded fetal PPG is that the fetal PPG signal is very weak and mixed with maternal PPG signal. In this paper we introduce a method based on QRS triggered averaging to separate the weak fetal PPG signal from the superimposed PPG signal. The approach has been successfully tested on a simple experimental setup with two probands as a substitute for mother and fetus.