title: Prediction of adverse perinatal outcome by cerebroplacental ratio adjusted for estimated fetal weight.
abstract: OBJECTIVE
  To evaluate the relationship between cerebroplacental ratio (CPR) and estimated fetal weight (EFW) in low- and high-risk singleton pregnancies. Furthermore, we evaluated the role of CPR in the prediction of adverse perinatal outcome and whether CPR measurements adjusted for EFW improve its predictive value.
  
  
  METHODS
  This was a retrospective cohort study including pregnancies in which Doppler investigations of umbilical artery (UA) and fetal middle cerebral artery (MCA) were performed at ≥ 30 weeks' gestation. Pregnancies were allocated to one of three groups according to EFW centile: small-for-gestational age (SGA) with EFW < 10thcentile, appropriate-for-gestational age (AGA) and large-for-gestational age (LGA) with EFW > 90thcentile. CPR was calculated as the ratio between the UA pulsatility index (PI) and MCA-PI and converted to CPR multiples of the median (MoMs) according to the three EFW groups. Linear regression analysis was performed to evaluate the relationship between CPR-MoMs and EFW centiles in low-risk pregnancies. Furthermore, MoMs of CPR adjusted according to EFW centile (aCPR-MoMs) were calculated. Adverse perinatal outcome was defined as presence of pathological cardiotocography (CTG) trace, arterial cord blood pH < 7.1, 5-min Apgar score < 7 and presence of meconium-stained amniotic fluid (MSAF).
  
  
  RESULTS
  A total of 3515 (3016 low risk and 499 high risk) pregnancies, delivered between January 2010 and March 2016, were included. Linear regression analysis revealed a significant positive correlation between EFW centile and CPR-MoM. Receiver-operating characteristics (ROC) curve analysis showed a significant association between CPR-MoM and pathological CTG trace (AUC, 0.539; SD, 0.014; P = 0.005) and low Apgar score (AUC, 0.609; SD, 0.041; P = 0.008), but not with low arterial pH or MSAF. There was a significant association between aCPR-MoM and pathological CTG trace (AUC, 0.540; SD, 0.014; P = 0.003), low arterial cord blood pH (AUC, 0.546; SD, 0.022; P = 0.035) and low Apgar score (AUC, 0.609; SD, 0.044; P = 0.008), but not with MSAF. However, detection rates for adverse perinatal outcomes by CPR-MoM and aCPR-MoM were low, ranging from 6.7% to 28.6% for SGA, 12.1% to 22.2% for AGA and 0% to 33.3% for LGA, for a false-positive rate of 10%. In a subgroup analysis of cases in which ultrasound examination was performed at ≥ 34 weeks of gestation and within 4 weeks of delivery (n = 1439), the ROC curves for aCPR-MoM were significantly associated with all four outcomes evaluated.
  
  
  CONCLUSIONS
  CPR-MoM values are dependent on EFW centiles; therefore, we suggest that CPR-MoM should be adjusted for EFW centile. However, both CPR- and aCPR-MoM showed a low prediction rate for adverse perinatal outcome. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.
authors.affiliation: Department of Obstetrics and Fetal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.|High Risk Pregnancy Centre-Department of Neurosciences, Reproductive and Dentistry Sciences, University Federico II, Naples, Italy.
authors.forename: A
authors.identifier: http://orcid.org/0000-0002-0593-9063
authors.initials: A
authors.lastname: Sirico
authors.affiliation: Department of Obstetrics and Fetal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: A
authors.identifier: http://orcid.org/0000-0003-2546-5464
authors.initials: A
authors.lastname: Diemert
authors.affiliation: Department of Obstetrics and Fetal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Glosemeyer
authors.affiliation: Department of Obstetrics and Fetal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: K
authors.identifier: http://orcid.org/0000-0002-3172-1164
authors.initials: K
authors.lastname: Hecher
mesh_terms: D000328:Adult; D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging*; D020567:Fetal Weight / Q000502:physiology*; D005333:Fetus / Q000098:blood supply; D005865:Gestational Age; D006801:Humans; D007236:Infant, Small for Gestational Age; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000196:embryology / Q000503:physiopathology; D010920:Placenta / Q000000981:diagnostic imaging; D010927:Placental Insufficiency / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000000981:diagnostic imaging*; D011263:Pregnancy Trimester, Third / Q000502:physiology; D011673:Pulsatile Flow / Q000502:physiology*; D012372:ROC Curve; D012189:Retrospective Studies; D018570:Risk Assessment; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal
keywords: Doppler; cerebroplacental ratio; estimated fetal weight; perinatal outcome; umbilical artery