Impact of childbirth on external anal sphincter electromyography / 中华神经科杂志

ABSTRACT

Objective To explore the impact of childbirth on women external anal sphincter electromyography by analysis of motor unit potentials parameters of external anal sphincter electromyography of healthy women volunteers with different childbirth experiences.Methods Twenty-eight healthy volunteers with different childbirth experiences were recruited in this study.Among them , 7 had a history of cesarean and 21 had experienced 1-3 uncomplicated vaginal deliveries ( 12 women had experienced 1, 6 had experienced 2, and 3 had experienced 3).Another 9 nulliparous healthy volunteers were recruited as control group.Among all subjects who completed the examination , parameters of motor unit potentials ( duration, amplitude, area, mean number of turns and mean phases ) of bilateral external anal sphincter were obtained for statistical analysis.Results There were no significant differences in any of the parameters of motor unit potentials between the nulliparous group and the cesarean group , while parameters of durations (10.5 ms vs 9.0 ms, t=-2.506, P=0.019) and mean phases (4.0 vs 3.6, t =-2.707, P=0.012) of vaginal delivery group were significantly higher than that of cesarean group and parameter of durations ( 10.5 ms vs 8.9 ms, t =-3.025, P =0.005 ) of vaginal delivery group was significantly higher than that of the nulliparous group;With increasing numbers of vaginal deliveries , only the parameter of mean turns showed statistically significant differences , although there was a slight trend of larger and more complex motor unit potentials.Compared with subjects without vaginal delivery experience ( including nulliparous group and the cesarean group ) , the parameters of durations and mean phases of subjects with vaginal delivery experience were statistically higher; Nevertheless , parameter of bilateral duration of the motor unit potential preferred asymmetric.Conclusions Childbirth experience has an explicit impact on the parameters of the external anal sphincter motor unit potentials , which is considered to be strongly correlated with the vaginal delivery process rather than the pregnancy procession itself.In addition , the impact is mostly from the first vaginal delivery experience.The characters of asymmetry of motor unit potential parameters imply the possibility of mechanical damage and decrease blood perfusion of tissues during delivery procession.