Computerized analysis of the maternal heart rate during labour using the Omniview-SisPorto system: electrocardiography versus photoplethysmography

Abstract

Background: Electronic fetal heart rate monitoring incorporating maternal heart rate (MHR) analysis may better anticipate fetal hypoxia, acidosis and labour dystocia, improving fetal surveillance. However, the performance of available MHR acquisition techniques during labour remains inadequately evaluated. The aim of this study was to compare intrapartum MHR simultaneously acquired by electrocardiography (ECG) and photoplethysmography (PPG). Methods: Fifty-two MHR recordings were simultaneously obtained by ECG and PPG, corresponding to the same number of women in labour, during the final two hours of labour (H1 and H2), each recording lasting >110 minutes. Differences, correlation and disagreement between ECG and PPG signals were, respectively, assessed using the Wilcoxon test, the Spearman correlation coefficient and the nonparametric measure of disagreement dAB. The following variables were evaluated: baseline, number of accelerations, number of decelerations, average and abnormal short-term variability, average and abnormal long-term variability. Results: Baseline obtained through PPG signal presented a strong correlation with ECG. The number of accelerations, average short- and long-term variability were significantly lower with PPG but with a good correlation. Abnormal short- and long-term variability were significantly higher with PPG, with lower correlation and higher disagreement. Discussion: Heart rate acquisition techniques from both ECG and PPG may yield signal disparities. ECG signals offer higher resolution, while PPG exhibits significantly lower average short-term variability, leading to elevated abnormal short-term variability. As no conclusive evidence has established ECG superiority in diagnostic capacity, computerized systems like Omniview-SisPorto should adapt their decision rules according to the chosen method.