title: Noninvasive monitoring of fetal heart rate during the last ten days of gestation in sows.
abstract: OBJECTIVE
  To develop and evaluate a noninvasive technique for monitoring and analyzing porcine fetal heart rate (FHR) during late gestation.
  
  
  METHODS
  8 fetuses of 8 pluriparous sows in late gestation.
  
  
  METHODS
  With the sow positioned in lateral recumbency, the most caudal fetus was identified, using real time ultrasonography, and its heart rate was recorded for 60 minutes by use of Doppler cardiography. The same fetus was identified and monitored repeatedly during the last 10 days of gestation, excluding the 24 hours before delivery. Visual inspection and computerized analysis of the recordings were performed.
  
  
  RESULTS
  66 one-hour recordings were obtained from 8 fetuses, 1 in each of 8 sows. Mean signal loss was 37.5%. Episodes of low FHR and low FHR variation (FHR pattern A) alternated with episodes of high FHR and high FHR variation (FHR pattern B). This cyclic alternation between 2 distinct. FHR patterns was observed in 46 of 66 (69.7%) recordings, and suggests the presence of different behavioral states in fetal pigs. Basal FHR decreased toward parturition in 7 fetuses, but increased in 1 fetus with abdominal ascites. Basal FHR and long-term FHR variation were negatively correlated (r[S] = -0.73; P < 0.001).
  
  
  CONCLUSIONS
  Noninvasive monitoring of FHR is possible and feasible during late gestation in pigs. This method permits longitudinal studies under pathophysiologic conditions and the evaluation of the effects of endogenous and exogenous influences on porcine FHR.
authors.affiliation: Department of Herd Health and Reproduction, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Cohen
authors.forename: E J
authors.initials: EJ
authors.lastname: Mulder
authors.forename: H A
authors.initials: HA
authors.lastname: van Oord
authors.forename: F H
authors.initials: FH
authors.lastname: Jonker
authors.forename: G C
authors.initials: GC
authors.lastname: van der Weijden
authors.forename: M A
authors.initials: MA
authors.lastname: Taverne
mesh_terms: D000818:Animals; D004452:Echocardiography / Q000379:methods / Q000662:veterinary; D015150:Echocardiography, Doppler / Q000379:methods / Q000662:veterinary; D005260:Female; D005323:Fetal Monitoring / Q000379:methods / Q000662:veterinary*; D005865:Gestational Age; D006321:Heart / Q000196:embryology* / Q000502:physiology; D006340:Heart Rate, Fetal / Q000502:physiology*; D008137:Longitudinal Studies; D011247:Pregnancy; D013552:Swine / Q000196:embryology* / Q000502:physiology; D018608:Ultrasonography, Doppler / Q000379:methods / Q000662:veterinary; D016216:Ultrasonography, Prenatal / Q000379:methods / Q000662:veterinary