title: Uterine electromyography during active phase compared with latent phase of labor at term.
abstract: BACKGROUND
  In a prospective study in a tertiary university hospital we wanted to determine whether uterine electromyography (EMG) can differentiate between the active and latent phase of labor.
  
  
  METHODS
  Thirty women presenting at ≥37(0/7) weeks of gestation with regular uterine contractions, intact membranes, and a Bishop score <6. EMG was recorded from the abdominal surface for 30 min. Latent phase was defined as no cervical change within at least 4 h. Student's t-test was used for statistical analysis (p ≤ 0.05 significant). Diagnostic accuracy of EMG was determined by receiver operator characteristics (ROC) analysis. The integral of the amplitudes of the power density spectrum (PDS) corresponding to the PDS energy within the "bursts" of uterine EMG activity was compared between the active and latent labor groups.
  
  
  RESULTS
  Seventeen (57%) women were found to be in the active phase of labor and 13 (43%) were in the latent phase. The EMG PDS integral was significantly higher (p = 0.02) in the active (mean 3.40 ± 0.82 μV) compared with the latent (mean 1.17 ± 0.33 μV) phase of labor. The PDS integral had an area under the ROC curve (AUC) of 0.80 to distinguish between active and latent phases of labor, compared with number of contractions on tocodynamometry (AUC = 0.79), and Bishop score (AUC = 0.78). The combination (sum) of PDS integral, tocodynamometry, and Bishop score predicted active phase of labor with an AUC of 0.90.
  
  
  CONCLUSIONS
  Adding uterine EMG measurements to the methods currently used in the clinics could improve the accuracy of diagnosing active labor.
authors.affiliation: Department of Perinatology, Division of Obstetrics and Gynecology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Andreja
authors.identifier: http://orcid.org/0000-0002-0196-2856
authors.initials: A
authors.lastname: Trojner Bregar
authors.affiliation: Department of Perinatology, Division of Obstetrics and Gynecology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Miha
authors.identifier: http://orcid.org/0000-0003-2708-9175
authors.initials: M
authors.lastname: Lucovnik
authors.affiliation: Department of Perinatology, Division of Obstetrics and Gynecology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Ivan
authors.identifier: http://orcid.org/0000-0001-6249-5799
authors.initials: I
authors.lastname: Verdenik
authors.affiliation: Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Franc
authors.identifier: http://orcid.org/0000-0002-5442-0209
authors.initials: F
authors.lastname: Jager
authors.affiliation: Department of Perinatology, Division of Obstetrics and Gynecology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Ksenija
authors.identifier: http://orcid.org/0000-0001-9088-2382
authors.initials: K
authors.lastname: Gersak
authors.affiliation: Department of Obstetrics and Gynecology, St Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
authors.forename: Robert E
authors.identifier: http://orcid.org/0000-0002-4938-3781
authors.initials: RE
authors.lastname: Garfield
mesh_terms: D000328:Adult; D015992:Body Mass Index; D004576:Electromyography / Q000379:methods*; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D017524:Slovenia; D014590:Uterine Contraction / Q000502:physiology*; D018590:Uterine Monitoring / Q000379:methods*
keywords: Uterine electromyography; active labor; electrohysterography; latent labor; power density spectrum