title: Changes in cerebral autoregulation in the second half of pregnancy and compared to non-pregnant controls.
abstract: OBJECTIVE
  The mechanism by which pregnancy affects the cerebral circulation is unknown, but it has a central role in the development of neurological complications in preeclampsia, which is believed to be related to impaired autoregulation. We evaluated the cerebral autoregulation in the second half of pregnancy, and compared this with a control group of healthy, fertile non-pregnant women.
  
  
  METHODS
  In a prospective cohort analysis, cerebral blood flow velocity of the middle cerebral artery (determined by transcranial Doppler), blood pressure (noninvasive arterial volume clamping), and end-tidal carbon dioxide (EtCO2) were simultaneously collected for 7min. The autoregulation index (ARI) was calculated. ARI values of 0 and 9 indicated absent and perfect autoregulation, respectively. ANOVA and Pearson's correlation coefficient were used, with p<0.05 considered significant.
  
  
  RESULTS
  A total of 76 pregnant and 18 non-pregnant women were included. The ARI did not change during pregnancy, but pregnant women had a significantly higher ARI than non-pregnant controls (ARI 6.7±0.9 vs. 5.3±1.4, p<0.001). This remained significant after adjusting for EtCO2 (p<0.001).
  
  
  CONCLUSIONS
  Cerebral autoregulation functionality is enhanced in the second half of pregnancy, when compared to non-pregnant fertile women, even after controlling for EtCO2. The autoregulation does not change with advancing gestational age.
authors.affiliation: University Medical Center Groningen, Department of Obstetrics and Gynaecology, Groningen, The Netherlands; Baylor College of Medicine, Department of Obstetrics and Gynecology, Houston, TX, USA. Electronic address: teelkien@gmail.com.
authors.forename: Teelkien R
authors.initials: TR
authors.lastname: van Veen
authors.affiliation: Department of Cardiovascular Sciences, University of Leicester, UK; NIHR Biomedical Research Unit in Cardiovascular Sciences, Glenfield Hospital, UK.
authors.forename: Ronney B
authors.initials: RB
authors.lastname: Panerai
authors.affiliation: St. David's Women's Center of Texas, North Austin Maternal-Fetal Medicine, Austin, TX, USA.
authors.forename: Sina
authors.initials: S
authors.lastname: Haeri
authors.affiliation: University Medical Center Groningen, Department of Obstetrics and Gynaecology, Groningen, The Netherlands.
authors.forename: Paul P
authors.initials: PP
authors.lastname: van den Berg
authors.affiliation: University Medical Center Groningen, Department of Obstetrics and Gynaecology, Groningen, The Netherlands.
authors.forename: Gerda G
authors.initials: GG
authors.lastname: Zeeman
authors.affiliation: Baylor College of Medicine, Department of Obstetrics and Gynecology, Houston, TX, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Belfort
mesh_terms: D000328:Adult; D001794:Blood Pressure; D001944:Breath Tests; D002245:Carbon Dioxide / Q000032:analysis; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D054022:Cerebrum / Q000502:physiology*; D005260:Female; D005865:Gestational Age; D006706:Homeostasis; D006801:Humans; D011247:Pregnancy / Q000502:physiology*; D011262:Pregnancy Trimester, Second / Q000502:physiology; D011263:Pregnancy Trimester, Third / Q000502:physiology; D011446:Prospective Studies; D017585:Ultrasonography, Doppler, Transcranial; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide
keywords: Autoregulation index; Cerebral autoregulation; Pregnancy; Transcranial Doppler