title: Characterization of abdominally acquired uterine electrical signals in humans, using a non-linear analytic method.
abstract: The present work seeks to determine if a particular non-linear analytic method is effective at quantifying uterine electromyography (EMG) data for estimating the onset of labor. Twenty-seven patients were included, and their uterine EMG was recorded non-invasively for 30 min. The patients were grouped into two sets: G1: labor, N = 14; G2: antepartum, N = 13. G1 patients all delivered spontaneously within 24 h of recording while G2 patients did not. The uterine electrical signals were analyzed offline by first isolating the uterine-specific frequency range and then randomly selecting "bursts" of uterine electrical activity (each associated with a uterine contraction) from every recording. Wavelet transform was subsequently applied to each of the bursts' traces, and then the fractal dimension (FD) of the resulting transformed EMG burst-trace was calculated (Benoit 1.3, Trusoft). Average burst FD was found for each patient. FD means for G1 and G2 were calculated and compared using t test. FD was significantly higher (P < 0.05) for G1: 1.27 +/- 0.03 versus G2: 1.25 +/- 0.02. The wavelet-decomposition-generated fractal dimension can be used to successfully discern between patients who will deliver spontaneously within 24 h and those who will not, and can be useful for the objective classification of antepartum versus labor patients.
authors.affiliation: Department of Obstetrics and Gynecology, Division of Reproductive Sciences, University of Texas Medical Branch, 301 University Route 1062, Galveston, TX 77555, USA. wlmaner@utmb.edu
authors.forename: William L
authors.initials: WL
authors.lastname: Maner
authors.forename: Lynette B
authors.initials: LB
authors.lastname: MacKay
authors.forename: George R
authors.initials: GR
authors.lastname: Saade
authors.forename: Robert E
authors.initials: RE
authors.lastname: Garfield
mesh_terms: D000005:Abdomen; D004576:Electromyography / Q000295:instrumentation / Q000379:methods; D005260:Female; D017709:Fractals; D006801:Humans; D007745:Labor Onset / Q000502:physiology*; D008954:Models, Biological; D019095:Point-of-Care Systems; D011247:Pregnancy; D014590:Uterine Contraction / Q000502:physiology*