title: Factors affecting uterine electrical activity during the active phase of labor prior to rupture of membranes.
abstract: OBJECTIVE
  Limited data exist regarding uterine contraction intensity prior to membrane rupture. Using a novel technique of electrical uterine myography (EUM) we aimed to determine which factors affect myometrial activity during active phase of labor.
  
  
  METHODS
  EUM was prospectively measured in 37 women with singleton pregnancy at term during the active phase of labor until membranes' rupture. EUM was measured using non-invasive nine channels recorder with an EMG amplifier and three-dimensional position sensor. Uterine electrical activity was quantified with the EUM-index, defined as the mean electrical activity of the uterine muscle over a period of 10 min and measured in units of micro-Joule (microwatt per second [mW/s]).
  
  
  RESULTS
  The mean EUM-index at the first 10 min of the measurement was 3.3 ± 0.6 mW/s. In a stepwise linear regression model accounting potential confounders EUM was significantly affected by cervical dilatation (p = 0.005), maternal age (p = 0.04) and previous cesarean delivery status (p = 0.02). In a repeated measurement assessment of non-parametric Fridman's test for all subjects who had at least 10 continuouss EUM measurements, there was a significant increase in electrical uterine activity as labor progressed (p = 0.01).
  
  
  CONCLUSIONS
  Electrical uterine activity during the active phase of labor prior to rupture of membranes is affected by maternal age, previous cesarean delivery status and cervical dilatation. Moreover, electrical uterine activity is enhanced throughout labor.
authors.affiliation: a Department of Obstetrics and Gynecology , Helen Schneider Hospital for Women, Rabin Medical Center , Petach Tikva , Israel and.
authors.forename: Liran
authors.initials: L
authors.lastname: Hiersch
authors.forename: Liat
authors.initials: L
authors.lastname: Salzer
authors.forename: Amir
authors.initials: A
authors.lastname: Aviram
authors.forename: Avi
authors.initials: A
authors.lastname: Ben-Haroush
authors.forename: Eran
authors.initials: E
authors.lastname: Ashwal
authors.forename: Yariv
authors.initials: Y
authors.lastname: Yogev
mesh_terms: D000328:Adult; D002585:Cesarean Section; D004576:Electromyography; D005260:Female; D006801:Humans; D007747:Labor Stage, First / Q000502:physiology; D007743:Labor, Obstetric / Q000502:physiology; D016014:Linear Models; D008423:Maternal Age; D009215:Myometrium / Q000502:physiology*; D011247:Pregnancy; D011446:Prospective Studies; D016037:Single-Blind Method; D014590:Uterine Contraction / Q000502:physiology*
keywords: Active phase; delivery; uterine activity