Characterization of EHG Contractions at Pregnancy and Term Labor by Multiscale Entropy Analysis

Monitoring uterine activity by electrohysterogram (EHG), associated with contractions both in pregnancy and labor, may contribute to the knowledge for evaluating possible risks to the binomial mother-fetus. In this context, the aim of the present study was to explore the complexity of EHG generated by women during the third trimester of pregnancy (group P) and at term labor (group L). The EHG was obtained by band-pass filtering in the range from 0.1 to 3 Hz the monopolar raw signal of the electrode number 1, of a 4-by-4 sensor array, which was located near to the tocodynamometer transducer. Multiscale entropy (MSE) analysis measures the entropy over multiple time scales to provide the complexity of the EHG time series. The results pointed out that such nonlinear technique has the potential to discriminate contractions from both groups using the area under the MSE curve (AUC) as index. The highest complexity was obtained for group P (N= 8) as AUC was 13.9233 ± 0.2015 while the lowest complexity was for group L, with N=8 and AUC of 5.1675 ± 0.0783 (p<; 0.0001). Consequently, the complexity of EHG by MSE could provide an index to discriminate between the electrical uterine activity generated during pregnancy or at labor.