title: Sporadic fetal heart rate decelerations associated with electrocortical changes in fetal lambs.
abstract: OBJECTIVE
  The purpose of this study was to determine a relationship between sporadic fetal heart rate (FHR) decelerations and fetal electrocortical changes in physiologically normal sheep fetuses.
  
  
  METHODS
  A total of 20 experimental observations were conducted on eight chronically instrumented fetal lambs. For electrocorticogram (ECoG) recording, two stainless steel electrodes were implanted bilaterally on the fetal parietal skull. Classifications of ECoG tracings were visually divided into periods of low, high, intermediate and transitional voltage. During day and night observations, sporadic FHR decelerations related to fetal ECoG changes were counted.
  
  
  RESULTS
  We found that 65% of the total sporadic FHR decelerations occurred in relation to fetal ECoG changes. The largest number of sporadic FHR decelerations was associated with a switch from low voltage to high voltage ECoG (37%). However, the greatest frequency of sporadic FHR decelerations occurred during intermediate ECoG periods (34%).
  
  
  CONCLUSIONS
  The majority of sporadic FHR decelerations observed in physiologically normal sheep fetuses were associated with fetal ECoG changes.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of California, Irvine, Orange, USA. fujimori@fmu.ac.jp
authors.forename: Keiya
authors.initials: K
authors.lastname: Fujimori
authors.forename: Yuji
authors.initials: Y
authors.lastname: Murata
authors.forename: Akira
authors.initials: A
authors.lastname: Sato
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000196:embryology* / Q000502:physiology*; D004567:Electrodes, Implanted; D004569:Electroencephalography; D005260:Female; D006340:Heart Rate, Fetal; D011247:Pregnancy; D012756:Sheep / Q000196:embryology