Table 2.

Mean and standard deviation values of the electrohysterography characteristics of VGN and CSR groups. Values in bold indicate the statistical difference between groups (α = 0.05). Effect size values are marked with (**) if large and with (*) if medium. KHE: Kurtosis of the Hilbert Envelope; KFD: Katz Fractal Dimension.

	CSR (μ ± σ)	VGN (μ ± σ)	p-Value	Effect Size
Peak-to-peak amp. (μV)	45.60 ± 20.78	66.44 ± 26.62	0.027	0.78 **
KHE	2.71 ± 0.39	2.30 ± 0.36	0.003	1.18 **
Median frequency (Hz)	0.31 ± 0.02	0.32 ± 0.01	0.086	0.76 **
Dominant frequency (Hz)	0.25 ± 0.02	0.26 ± 0.02	0.258	0.42 *
NE	0.31 ± 0.04	0.34 ± 0.03	0.04	0.80 **
Binary Lempel-Ziv	0.39 ± 0.05	0.37 ± 0.08	0.155	0.31 *
Sample Entropy	0.92 ± 0.18	0.88 ± 0.23	0.451	0.19
Spectral Entropy	0.89 ± 0.02	0.88 ± 0.02	0.019	0.69 **
KFD	1.05 ± 0.03	1.08 ± 0.03	0.004	1.00 **

Both median frequency (VGN 0.32 ± 0.01 vs. CSR 0.31 ± 0.02) and dominant frequency (VGN 0.26 ± 0.02 vs. CSR 0.25 ± 0.02 Hz) of the spectral parameters were slightly higher in the VGN than CSR group and no statistical differences were found, with effect sizes of 0.76 and 0.42 correspondingly. Statistical difference between VGN and CSR spectral parameters was obtained for NE (VGN 0.34 ± 0.03 vs. CSR 0.31 ± 0.04, p-value= 0.04 and effect size of 0.8).