title: Uterine artery Doppler flow velocity waveforms in the second trimester for the prediction of preeclampsia and fetal growth retardation.
abstract: OBJECTIVE
  To determine the optimal method of measuring uterine artery waveforms with Doppler ultrasound when screening healthy nulliparas for subsequent development of preeclampsia and fetal growth retardation (FGR).
  
  
  METHODS
  Color Doppler ultrasound was used to obtain uterine artery waveforms at 19-24 weeks' gestation in 458 nulliparas. In each uterine artery, the resistance index (RI), the ratio between peak systolic (A) and early diastolic (C) blood flow velocities (AC ratio) (a measure of the early notch in the uterine artery waveform), and placental position were recorded. The predictive values of these uterine artery Doppler measurements were evaluated for pregnancy complications. The major end points were preeclampsia and small for gestational age (SGA) infants.
  
  
  RESULTS
  The best screening test for preeclampsia and SGA infants was the placental-side uterine artery RI or AC ratio above the 90th percentile for gestational age when the placenta was located on the left or right, and the highest RI or AC ratio when the placenta was midline. This method identified 51% of women with subsequent preeclampsia or SGA infants and had a positive predictive value of 29%. The test detected women with severe disease requiring delivery before 37 weeks with a sensitivity of 83% and specificity of 88%. However, the results were similar if the placental-side uterine artery RI was above an arbitrary cutoff of 0.56 or the AC ratio was above 2.05. A normal test predicted an uncomplicated pregnancy.
  
  
  CONCLUSIONS
  Although abnormal uterine artery Doppler is associated with an increased risk of preeclampsia and FGR, the positive predictive values do not support its introduction as a routine screening test in nulliparous women.
authors.affiliation: Ultrasound Department, Royal Women's Hospital, Melbourne, Victoria, Australia.
authors.forename: R A
authors.initials: RA
authors.lastname: North
authors.forename: C
authors.initials: C
authors.lastname: Ferrier
authors.forename: D
authors.initials: D
authors.lastname: Long
authors.forename: K
authors.initials: K
authors.lastname: Townend
authors.forename: P
authors.initials: P
authors.lastname: Kincaid-Smith
mesh_terms: D001158:Arteries / Q000000981:diagnostic imaging; D001783:Blood Flow Velocity; D003971:Diastole; D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging* / Q000517:prevention & control; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008403:Mass Screening; D011225:Pre-Eclampsia / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000517:prevention & control; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013599:Systole; D016216:Ultrasonography, Prenatal; D014599:Uterus / Q000098:blood supply* / Q000000981:diagnostic imaging*; D014655:Vascular Resistance