title: Placental pulsatility index: a new, more sensitive parameter for predicting adverse outcome in pregnancies suspected of fetal growth restriction.
abstract: BACKGROUND
  The pulsatility indices of the umbilical and uterine arteries are used as the surrogate measures of utero-placental perfusion. Combining the two might simplify the evaluation of total placental vascular impedance, possibly improve prediction of adverse outcomes, and help identify pregnancies with suspected fetal growth restriction that need more intense surveillance.
  
  
  METHODS
  Umbilical and uterine blood flow velocities were recorded using pulsed-wave Doppler in a longitudinal study of 53 low-risk pregnancies (248 observations) during 20-40 weeks of gestation. Pulsatility indices was calculated for each of these vessels. A new placental pulsatility index was constructed as: (umbilical artery pulsatility index + mean of the left and right uterine artery pulsatility indices)/2, and mean +2 SD defined as abnormal. Gestational age-specific reference percentiles were calculated for the second half of pregnancy and related to values obtained from 340 pregnancies with suspected intra-uterine growth restriction to test its ability to predict adverse pregnancy outcome.
  
  
  RESULTS
  The placental pulsatility index was closely associated with gestational age and decreased with advancing gestation in normal pregnancy. The placental pulsatility index had a higher sensitivity and comparable specificity in predicting adverse outcome in pregnancies suspected of intra-uterine fetal growth restriction when compared with conventional umbilical and uterine artery pulsatility indices.
  
  
  CONCLUSIONS
  The new placental pulsatility index, reflecting placental vascular impedance on both the fetal and maternal side of placenta, improves prediction of adverse outcome in pregnancies suspected of intra-uterine fetal growth restriction.
authors.affiliation: Department of Obstetrics and Gynecology, Skane University Hospital, University of Lund, Malmö, Sweden.
authors.forename: Saemundur
authors.identifier: http://orcid.org/0000-0001-9738-9355
authors.initials: S
authors.lastname: Gudmundsson
authors.affiliation: Women's Health and Perinatology Research Group, Department of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.|Department of Obstetrics and Gynecology, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Kari
authors.identifier: http://orcid.org/0000-0003-2276-1508
authors.initials: K
authors.lastname: Flo
authors.affiliation: Department of Obstetrics and Gynecology, Skane University Hospital, University of Lund, Malmö, Sweden.
authors.forename: Gisela
authors.initials: G
authors.lastname: Ghosh
authors.affiliation: Department of Community Medicine, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway.
authors.forename: Tom
authors.identifier: http://orcid.org/0000-0002-2709-9472
authors.initials: T
authors.lastname: Wilsgaard
authors.affiliation: Women's Health and Perinatology Research Group, Department of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.|Department of Obstetrics and Gynecology, University Hospital of North Norway, Tromsø, Norway.|Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm, Sweden.
authors.forename: Ganesh
authors.identifier: http://orcid.org/0000-0002-1997-3107
authors.initials: G
authors.lastname: Acharya
mesh_terms: D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D005260:Female; D005313:Fetal Death; D005317:Fetal Growth Retardation / Q000503:physiopathology; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008137:Longitudinal Studies; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth; D011673:Pulsatile Flow / Q000502:physiology*; D012680:Sensitivity and Specificity; D018617:Ultrasonography, Doppler, Pulsed; D014469:Umbilical Arteries / Q000000981:diagnostic imaging / Q000502:physiology*; D055988:Uterine Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D055815:Young Adult
keywords: Doppler; Placenta pulsatility index; fetal growth restriction; pregnancy; small for gestational age; umbilical artery; uterine artery