Groups N Age Amp (μV) Dur (ms) Number of turns Number of phases Area (μVms) Satellite Rate       mean SD mean SD mean SD mean SD mean SD mean SD Total 62 41.9 533.41 87.41 9.92 1.31 3.72 0.49 3.84 0.39 474.17 122.92 0.07 0.05 Male 25 43.2 546.39 71.52 10.05 1.07 3.75 0.49 3.86 0.41 517.13 148.45 0.05 0.05 Female 37 41.0 524.63 96.64 9.84 1.46 3.70 0.49 3.84 0.38 445.15 93.60 0.08 0.06 VA 21 46.0 515.00 78.27 10.52 1.51 3.82 0.48 3.98 0.31 442.41 88.11 0.10 0.06 CA 7 45.3 572.03 138.16 9.00 0.85 3.46 0.29 3.60 0.37 479.67 117.31 0.05 0.03 NU 9 26.2 510.25 99.79 8.91 0.73 3.61 0.58 3.70 0.44 424.69 90.36 0.05 0.05

Table 1: Means and standard deviations of the external anal sphincter EMG parameters for each group; VA, vaginal delivery; CA, caesarean; NU, nulliparous; Amp., amplitude; Dur., duration.