title: Specific change in spectral power of fetal heart rate variability related to fetal acidemia during labor: comparison between preterm and term fetuses.
abstract: BACKGROUND
  Spectral analysis of fetal heart rate (FHR) variability is a useful method to assess fetal condition. There have been several studies involving the change in spectral power related to fetal acidemia, but the results have been inconsistent.
  
  
  OBJECTIVE
  To determine the change in spectral power related to fetal umbilical arterial pH at birth, dividing cases into preterm (31-36 weeks) and term (≥37 weeks) gestations.
  
  
  METHODS
  Case-control study. The 514 cases of deliveries were divided into a low-pH group (an umbilical arterial pH <7.2) and a control group (pH≥7.2).
  
  
  METHODS
  FHR recorded on cardiotocography during the last 2h of labor.
  
  
  METHODS
  The spectral powers in various bands of FHR variability.
  
  
  RESULTS
  In preterm fetuses, the total, low (LF), and movement (MF) frequency spectral powers and LF/HF ratio were significantly lower in the low-pH group than the control group (all P<0.05). In contrast, in term fetuses, the total frequency, LF, and MF powers were significantly higher in the low-pH group than the control group (all P<0.05). The area under the receiver operating characteristic of LF power to detect a low pH at birth was 0.794 in preterm fetuses and 0.595 in term fetuses. The specificity was 86.8% and 93.3% in preterm and term fetuses, respectively.
  
  
  CONCLUSIONS
  The changes in spectral power responding to a low pH are different between term and preterm fetuses. Spectral analysis of FHR variability may be useful fetal monitoring for early detection of fetal acidemia.
authors.affiliation: Department of Obstetrics and Gynecology, the Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Kwon
authors.forename: In Yang
authors.initials: IY
authors.lastname: Park
authors.forename: Jong Chul
authors.initials: JC
authors.lastname: Shin
authors.forename: Juhee
authors.initials: J
authors.lastname: Song
authors.forename: Reza
authors.initials: R
authors.lastname: Tafreshi
authors.forename: Jongil
authors.initials: J
authors.lastname: Lim
mesh_terms: D000138:Acidosis / Q000150:complications / Q000151:congenital / Q000503:physiopathology*; D000328:Adult; D015148:Cardiotocography / Q000379:methods; D002318:Cardiovascular Diseases / Q000151:congenital / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D005323:Fetal Monitoring / Q000379:methods; D005865:Gestational Age; D006340:Heart Rate, Fetal / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D007234:Infant, Premature / Q000502:physiology; D007235:Infant, Premature, Diseases / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D007744:Obstetric Labor Complications / Q000175:diagnosis / Q000503:physiopathology*; D011247:Pregnancy; D047929:Term Birth