Improving the classification rate of labor vs. normal pregnancy contractions by using EHG multichannel recordings

Most of the studies on the synchronization between EHG signals, recorded during the same contractions at different locations, are limited to the use of only two channels. Multichannel techniques have however been widely applied to EEG signals but rarely to EHG. In this paper, we investigate the use of multichannel uterine EMG signals for classifying contractions. We compare the performance of phase synchronization in distinguishing between labor and normal pregnancy contractions by using either only two channels or a 4x4 matrix positioned on the woman's abdomen. We used two indexes to measure the phase synchronization: mean phase coherence and phase entropy. ROC curves indicate that the use of multichannel signals can significantly improve the classification rate of pregnancy and labor contractions.