title: [Cerebroplacental ratio and acidemia to the birth in placental insufficiency detected before 34th week's gestation].
abstract: OBJECTIVE
  to evaluate the hypothesis that the fetal cerebroplacental ratio (CPR) is related to acidemia at birth in pregnancies complicated by placental insufficiency detected before 34 weeks of gestation.
  
  
  METHODS
  this is a prospective cohort study of 55 patients between 26 and 34 weeks of gestation with a diagnosis of placental insufficiency characterized by abnormal umbilical artery Doppler (pulsatility index>95 p). Fetal assessment was performed for each patient by dopplervelocimetry of the umbilical artery, middle cerebral artery and ductus venosus, and by the fetal biophysical profile. CPR was calculated using the ratio between middle cerebral artery pulsatility index and umbilical artery pulsatility index, and the z-score was obtained (number of standard deviations of the mean value at each gestational age). Acidemia at birth was characterized when pH<7.2.
  
  
  RESULTS
  of 55 patients, 29 (52.7%) presented acidemia at birth. In the group of fetal acidemia, when compared with the group with pH>7.2, a significant association was observed with CPR values (median 0.47 versus 0.58; p=0.009), pulsatility index of the umbilical artery (median 2.45 versus 1.93; p=0.003), ductus venosus pulsatility index for veins (PIV) (median 1.08 versus 0.85; p=0.034) and suspected or abnormal fetal biophysical profile (37 versus 8%; p=0.031). CPR analysis by z-score showed a negative tendency, but was not statistically significant (p=0.080). Significant correlations were found between pH at birth and CPR (r=0.45; p<0.01), z-score of CPR (r=0.27; p<0.05) and ductus venosus PIV (r=-0.35 p<0.01).
  
  
  CONCLUSIONS
  CPR is associated with the presence of acidemia at birth in pregnancies with placental insufficiency detected before 34 weeks of gestation and this parameter could potentially represent a factor for assessing the severity of fetal involvement.
authors.affiliation: Departamento de Obstetrícia e Ginecologia, Faculdade de Medicina, Universidade de São Paulo – USP – São Paulo (SP), Brasil.
authors.forename: Mariane de Fatima Yukie
authors.initials: Mde F
authors.lastname: Maeda
authors.forename: Roseli Mieko Yamamoto
authors.initials: RM
authors.lastname: Nomura
authors.forename: Juliana Ikeda
authors.initials: JI
authors.lastname: Niigaki
authors.forename: Seizo
authors.initials: S
authors.lastname: Miyadahira
authors.forename: Marcelo
authors.initials: M
authors.lastname: Zugaib
mesh_terms: D000138:Acidosis / Q000503:physiopathology*; D000328:Adult; D001783:Blood Flow Velocity; D005260:Female; D006402:Hematologic Diseases / Q000503:physiopathology*; D006801:Humans; D007231:Infant, Newborn; D020768:Middle Cerebral Artery / Q000502:physiology*; D010927:Placental Insufficiency; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D014469:Umbilical Arteries / Q000502:physiology*