title: Assessment of maternal heart-rate variability during labor using wavelet-based power spectral analysis.
abstract: OBJECTIVE
  Changes in the maternal cardiac autonomic nervous system were assessed in the presence and absence of uterine contractions by analyzing maternal heart-rate variability during labor using wavelet-based power spectral analysis.
  
  
  METHODS
  We assessed the heart-rate variability in 20 pregnant women during labor and in 15 pregnant women with threatened premature labor with the use of wavelet-based power spectral analysis.
  
  
  RESULTS
  There was no significant difference in high-frequency components between the uterine contraction and non-contraction periods. The intensities of the low-frequency and very-low-frequency components during uterine contractions were significantly stronger than the corresponding intensities between uterine contractions.
  
  
  CONCLUSIONS
  Maternal sympathetic activity was upregulated during uterine contractions, and influenced the very-low-frequency components. This method of analysis may represent a novel means of identifying uterine contractions.
authors.affiliation: Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Noritsugu
authors.initials: N
authors.lastname: Suzuki
authors.forename: Junichi
authors.initials: J
authors.lastname: Sugawara
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kimura
authors.forename: Satoru
authors.initials: S
authors.lastname: Nagase
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Okamura
authors.forename: Nobuo
authors.initials: N
authors.lastname: Yaegashi
mesh_terms: D000328:Adult; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007743:Labor, Obstetric / Q000502:physiology*; D007752:Obstetric Labor, Premature / Q000503:physiopathology; D011247:Pregnancy; D014590:Uterine Contraction / Q000502:physiology; D058067:Wavelet Analysis; D055815:Young Adult