title: Fetal hemodynamic changes after amniotomy.
abstract: BACKGROUND
  The aim of the study was to assess fetal vascular blood flow after amniotomy.
  
  
  METHODS
  This was a prospective observational study. Thirty-five women with singleton pregnancy beyond 36 weeks of gestation, who underwent amniotomy, were recruited. The pulsatility indices of the fetal middle cerebral artery (MCA), the renal artery, and the ductus venosum were measured before and 30 min following amniotomy. The changes in pulsatility index were compared by means of Wilcoxon signed rank test.
  
  
  RESULTS
  There was a significant reduction in pulsatility indices of the MCA (median reduction: 0.23; interquantile range (IQR): -0.04, 0.4) and the renal artery (median reduction: 0.12; IQR: -0.12, 0.54) after amniotomy. However, there was no obvious change in the ductus venosum (median reduction: 0.00; IQR: -0.06, 0.1).
  
  
  CONCLUSIONS
  Amniotomy is associated with significant reduction in the impedance of the fetal MCA and the renal artery. The former may be a result of fetal stress response and the latter could be related to the release of vasoactive substances after amniotomy.
authors.affiliation: Department of Obstetrics and Gynecology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong. angelfok@cuhk.edu.hk
authors.forename: Wing Yee
authors.initials: WY
authors.lastname: Fok
authors.forename: Tak Yeung
authors.initials: TY
authors.lastname: Leung
authors.forename: Michelle Hy
authors.initials: MH
authors.lastname: Tsui
authors.forename: Tse Ngong
authors.initials: TN
authors.lastname: Leung
authors.forename: Tze Kin
authors.initials: TK
authors.lastname: Lau
mesh_terms: D000328:Adult; D000650:Amnion / Q000601:surgery*; D001783:Blood Flow Velocity; D015331:Cohort Studies; D005260:Female; D005323:Fetal Monitoring; D005333:Fetus / Q000098:blood supply*; D005500:Follow-Up Studies; D006340:Heart Rate, Fetal / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007751:Labor, Induced / Q000379:methods; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011295:Prenatal Care / Q000379:methods; D011446:Prospective Studies; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal