title: Neonatal Acid-Base Status in Fetuses with Abnormal Vertebro- and Cerebro-Placental Ratios.
abstract: OBJECTIVE
  A low cerebro-placental ratio (CPR) at term suggests the existence of failure to reach growth potential (FRGP) with a higher risk of poor neonatal acid-base status. This study aimed to evaluate whether similar findings were also seen in the vertebral artery (vertebro-placental ratio, VPR), supplying 30% of the cerebral flow.
  
  
  METHODS
  We studied term fetuses classified into groups according to birth weight (BW), CPR and VPR. BW was expressed in centiles and ratios in multiples of the median (MoM). Subsequently, associations with neonatal pH values were evaluated by means of regression curves and Mann-Whitney tests.
  
  
  RESULTS
  VPR MoM correlated with BW centiles (p < 0.0001, R2 = 0.042) and its distribution resembled that of CPR MoM (p < 0.001). When both arteries were compared, adequate-for-gestational-age (AGA) fetuses with either low CPR or low VPR had lower neonatal venous pH values (p < 0.05, p < 0.01, respectively). However, in case of small-for-gestational-age (SGA) fetuses, only those with low VPR had significantly lower neonatal arterial and venous pH values (p < 0.05).
  
  
  CONCLUSIONS
  Blood flow in the vertebral artery mimics that in the middle cerebral artery supporting the FRGP model. Both CPR and VPR identify AGA fetuses with lower neonatal pH values, but only VPR identifies SGA with lower pH values. Hypoxemia might be reflected as a generalized cerebral vasodilation demonstrated as low CPR and VPR.
authors: Servicio de Obstetricia, Hospital Universitario y Politécnico La Fe, Valencia, Spain.
authors: José
authors: J
authors: Morales-Roselló
authors: Asma
authors: A
authors: Khalil
authors: Blanca
authors: B
authors: Ferri-Folch
authors: Alfredo
authors: A
authors: Perales-Marín
mesh_terms: D000136:Acid-Base Equilibrium / Q000502:physiology*; D000328:Adult; D001921:Brain / Q000254:growth & development / Q000378:metabolism; D015331:Cohort Studies; D004453:Echoencephalography / Q000379:methods; D005260:Female; D005317:Fetal Growth Retardation / Q000097:blood* / Q000000981:diagnostic imaging*; D005333:Fetus; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal / Q000379:methods; D014711:Vertebral Artery / Q000000981:diagnostic imaging* / Q000254:growth & development