Direct graphical analysis of the fetal heart rate variability during labor

In this paper, a graphic analysis technique is applied to evaluate the fetal heart rate variability (HRV) extracted from fetal electrocardiogram (FECG) signals recorded directly from the abdominal wall of pregnant women during their labor phase. First, the FECG is extracted from the abdominal composite recordings by using a combination of two techniques: Periodic Component Analysis (PiCA) and Recursive Least Squares (RLS) adaptive filtering. Then, the fetal HRV is assessed with the nonlinear Poincaré plot analysis. The experimental results show that the Poincaré plot analysis can be successfully used on the extracted FECG signal to directly evaluate the fetal HRV without the need of using any external reference signal.