Comparing uterine electromyography activity of antepartum patients versus term labor patients

Objective The purpose of this study was to compare uterine electromyography of patients delivering >24 hours from measurement with laboring patients ≤24 hours from measurement. Study design Fifty patients (group 1: labor, n = 24; group 2: antepartum, n = 26) were monitored using transabdominal electrodes. Group 2 was recorded at several gestations. Uterine electrical “bursts” were analyzed by power-spectrum from 0.34 to 1.00 Hz. Average power density spectrum (PDS) peak frequency for each patient was plotted against gestational age, and compared between group 1 and group 2. Frequency was partitioned into 6 bins, and associated burst histograms compared. Results Group 1 was significantly higher than group 2 for gestational age (39.87 ± 1.08 vs 32.96 ± 4.26 weeks) and average PDS peak frequency (0.51 ± 0.10 vs 0.40 ± .03 Hz). Histograms were significantly different. A correlation coefficient of .41, with significance, was found with PDS vs gestation. Conclusion Uterine electromyography in antepartum patients is significantly lower than in laboring patients delivering ≤24 hours from measurement.