Analysis of the Maternal Cardio-Electrohysterographic Coupling During Labor by Bivariate Phase-Rectified Signal Averaging

Abstract

Maternal cardio-electrohysterographic coupling (MCEC), which is defined as the interaction of uterine electrical activity and maternal heart rate, is a physiological phenomenon poorly explored in the obstetric field. In this work, we evaluated the mechanism of MCEC before and during labor based on the Bivariate Phase-Rectified Signal Averaging Analysis (BPRSA). A group of women in the third trimester of pregnancy (TT = 44) and another group during active labor (AL = 51) were studied at the Maternal and Childbirth Research Centre (CIMIGen, Mexico City). We extracted 20 min of maternal heart-rate time series as well as the envelopes of the uterine electrical activity signals (electrohysterogram) obtained from a high-frequency recorded electrocardiogram. The coupling between uterine electrical activity and maternal heart rate was analyzed by BPRSA. Significant differences were found between TT vs. AL for cross-correlation of BPRSA signals (0.93 vs. 0.97, p < 0.01), respectively. These results suggest that during active labor, a higher MCEC is observed in comparison to the third trimester of pregnancy. The presence of increased MCEC could be involved in the physiological manifestation of labor.