title: Can the degree of retrograde diastolic flow in abnormal umbilical artery flow velocity waveforms predict pregnancy outcome?
abstract: OBJECTIVE
  Reverse end-diastolic flow is the most pathological type of the umbilical artery flow velocity waveform. We aimed to investigate whether additional prognostic information can be obtained from umbilical artery waveforms in cases with reverse end-diastolic flow.
  
  
  METHODS
  Umbilical artery Doppler velocity waveforms from 44 fetuses with reverse end-diastolic flow were analyzed and the following parameters measured: the highest amplitude and the area below the maximum velocity curve of forward and reverse flow (A, B and C, D, respectively) and the duration of forward and reverse flow (Tc and Td, respectively). Ratios A/B, C/D and Tc/Td were calculated. The cut-off values for A/B, C/D and Tc/Td with the best predictive values for perinatal death were established with the help of receiver operating characteristics curves. The three curves were compared with each other.
  
  
  RESULTS
  Of the three ratios, A/B and C/D had the best capacity to predict perinatal death. Both ratios had acceptable sensitivities, specificities and positive predictive values. In this regard, A/B and C/D were comparable. The cut-off values for A/B and C/D were 4.3 and 4.52, respectively. Survivors had I significantly higher A/B and C/D ratios than non-survivors (P = 0.0001 and 0.0003, respectively). Significantly more fetuses with A/B or C/D below the established cut-off values had pulsations in the venous system (P < 0.05). In fetuses with a gestational age < =210 gestational days the survival rate was significantly higher in those with A/B or C/D above the cut-off values (P = 0.03 and 0.003, respectively).
  
  
  CONCLUSIONS
  The A/B or C/D ratio can be used for quantification of the reverse end-diastolic flow waveforms in the umbilical artery and may offer additional information to the evaluation of fetal condition.
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Lund, Sweden. brodszki@minpot.nu
authors.forename: J
authors.initials: J
authors.lastname: Brodszki
authors.forename: E
authors.initials: E
authors.lastname: Hernandez-Andrade
authors.forename: S
authors.initials: S
authors.lastname: Gudmundsson
authors.forename: M
authors.initials: M
authors.lastname: Dubiel
authors.forename: G P
authors.initials: GP
authors.lastname: Mandruzzato
authors.forename: R
authors.initials: R
authors.lastname: Laurini
authors.forename: K
authors.initials: K
authors.lastname: Marsál
mesh_terms: D001783:Blood Flow Velocity; D003971:Diastole / Q000502:physiology; D005260:Female; D005313:Fetal Death; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology*; D005323:Fetal Monitoring / Q000379:methods*; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011336:Probability; D011446:Prospective Studies; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D015996:Survival Rate; D018608:Ultrasonography, Doppler / Q000379:methods; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000000981:diagnostic imaging* / Q000503:physiopathology