title: The vertebroplacental ratio as an alternative to the cerebroplacental ratio in the evaluation of the fetus at the end of pregnancy.
abstract: OBJECTIVE
  Low cerebroplacental ratio (CPR) near term has emerged as a marker of fetal adverse outcome. The aim of this study was to evaluate the predictive accuracy of an alternative ratio using the vertebral artery (VA) (vertebroplacental ratio or VPR) for acid-base status at birth.
  
  
  METHODS
  This was a prospective cohort study of 1470 pregnancies undergoing an ultrasound assessment of the umbilical artery, middle cerebral artery and VA Doppler beyond 34 weeks' gestation within 14 days of delivery. The CPR multiples of the median (MoM) and VPR MoM were calculated to adjust for gestational age. The relationship between the fetal Dopplers and the umbilical cord pH (arterial and venous) was evaluated statistically, and depicted graphically using three-dimensional (3D) trend surfaces, 2D contour graphs and ROC curves.
  
  
  RESULTS
  All the studied parameters were poorly associated with neonatal acid-base status, although this association was slightly better for venous pH. The importance of BW centile was smaller than that of CPR and VPR MoM, however, both hemodynamic parameters were similarly associated with neonatal pH.
  
  
  CONCLUSIONS
  Concerning fetal surveillance near term, the importance of cerebroplacental hemodynamics surpasses that of BW. Furthermore, in the evaluation of fetal wellbeing VPR behaves as a valid alternative to CPR.
authors.affiliation: a Servicio de Obstetricia, Hospital Universitario y Politécnico La Fe , Valencia , Spain.
authors.forename: José
authors.initials: J
authors.lastname: Morales-Roselló
authors.affiliation: c Fetal Medicine Unit , St George Hospital, University of London , London , UK.
authors.forename: Asma
authors.initials: A
authors.lastname: Khalil
authors.affiliation: b Unidad de Bioestadística, Instituto de Investigación Sanitaria La Fe , Valencia , Spain.
authors.forename: Victoria
authors.initials: V
authors.lastname: Fornés-Ferrer
authors.affiliation: b Unidad de Bioestadística, Instituto de Investigación Sanitaria La Fe , Valencia , Spain.
authors.forename: David
authors.initials: D
authors.lastname: Hervas-Marín
authors.affiliation: d Servicio de epidemiología, Hospital Universitario y Politécnico La Fe , Valencia , Spain.
authors.forename: Nuria
authors.initials: N
authors.lastname: Peralta-Llorens
authors.affiliation: a Servicio de Obstetricia, Hospital Universitario y Politécnico La Fe , Valencia , Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Rubio-Moll
authors.affiliation: a Servicio de Obstetricia, Hospital Universitario y Politécnico La Fe , Valencia , Spain.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Perales-Marín
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal / Q000379:methods*; D014469:Umbilical Arteries / Q000000981:diagnostic imaging*; D014711:Vertebral Artery / Q000000981:diagnostic imaging*
keywords: Cerebroplacental ratio; fetal Doppler; fetal growth restriction; vertebroplacental ratio