title: Reference ranges for umbilical and middle cerebral artery pulsatility index and cerebroplacental ratio in prolonged pregnancies.
abstract: OBJECTIVE
  To construct normal ranges for umbilical artery pulsatility index (UA PI), middle cerebral artery pulsatility index (MCA PI) and cerebroplacental ratio (CPR) in prolonged pregnancies according to strict methodological criteria using polynomial regression analysis.
  
  
  METHODS
  This was a retrospective, cross-sectional observational study involving 140 women, 10 women for each gestational day between 287 and 300 days of gestation. Fetal Doppler parameters were assessed to construct normal reference ranges for UA PI and MCA PI. CPR was calculated as a ratio of MCA PI/UA PI.
  
  
  RESULTS
  Mathematical modeling of the data demonstrated that the optimal fit was a linear polynomial one. Mean, 5th and 95th centiles were calculated for UA, MCA and CPR and centile curves from the regression analysis were constructed.
  
  
  CONCLUSIONS
  Reference ranges for UA PI, MCA PI and CPR in prolonged pregnancies have been constructed. MCA PI shows a wider range than previously reported in the literature.
authors.affiliation: Institut Clínic de Ginecologia, Obstetrícia i Neonatologia, Hospital Clínic de Barcelona, Barcelona, Spain. mpalacio@clinic.ub.es
authors.forename: M
authors.initials: M
authors.lastname: Palacio
authors.forename: F
authors.initials: F
authors.lastname: Figueras
authors.forename: L
authors.initials: L
authors.lastname: Zamora
authors.forename: J M
authors.initials: JM
authors.lastname: Jiménez
authors.forename: B
authors.initials: B
authors.lastname: Puerto
authors.forename: O
authors.initials: O
authors.lastname: Coll
authors.forename: V
authors.initials: V
authors.lastname: Cararach
authors.forename: J A
authors.initials: JA
authors.lastname: Vanrell
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005333:Fetus / Q000098:blood supply*; D005865:Gestational Age; D006801:Humans; D017078:Laser-Doppler Flowmetry; D020768:Middle Cerebral Artery / Q000196:embryology / Q000502:physiology*; D011247:Pregnancy; D011273:Pregnancy, Prolonged / Q000502:physiology*; D011673:Pulsatile Flow; D012016:Reference Values; D012189:Retrospective Studies; D014469:Umbilical Arteries / Q000196:embryology / Q000502:physiology*