title: The predictive value of 18 and 22 week uterine artery Doppler in patients with low first trimester maternal serum PAPP-A.
abstract: OBJECTIVE
  To determine if the addition of uterine artery (UA) Doppler pulsatility index (PI) at 18 and 22 weeks of gestation improves the predictive accuracy of low first trimester pregnancy associated plasma protein A (PAPP-A) in the detection of adverse obstetrical outcomes.
  
  
  METHODS
  This was a prospective interventional study. All women undergoing first trimester combined screening (FTS) at a single center, with a low maternal serum PAPP-A level (<0.4 MoM), were included. Patients underwent bilateral UA Doppler assessments at 18 and 22 weeks of gestation. A positive test was defined as a mean PI > 1.45. Primary outcomes were obtained from chart review, and logistic regression analysis was used to compare outcomes with positive and negative tests. Positive and negative predictive value, specificity and sensitivity were calculated.
  
  
  RESULTS
  Between January and October 2007, 5359 women completed FTS. Among the low PAPP-A group (n = 289), 18 week UA Doppler was a significant predictor of low birth weight (OR = 2.28, p = 0.04) while 22 week UA Doppler significantly predicted preterm birth (OR = 12.6, p = 0.001), small for gestational age (OR = 8.24, p = 0.001) and low birth weight (OR = 2.28, p = 0.04). Test characteristics suggested improved positive and negative predictive value for Doppler at 22 versus 18 weeks for these outcomes.
  
  
  CONCLUSIONS
  UA Doppler at 22 weeks is a useful adjunct in patients with low PAPP-A. However, a negative Doppler does not rule out all adverse outcomes and clinical judgment is advised in the management of these patients.
authors.affiliation: Division of Maternal Fetal Medicine, Departments of Obstetrics and Gynaecology and Community Health Sciences, University of Calgary, Calgary, Canada. Stephanie.Cooper@CalgaryHealthRegion.ca
authors.forename: Stephanie
authors.initials: S
authors.lastname: Cooper
authors.forename: Jo-Ann M
authors.initials: JA
authors.lastname: Johnson
authors.forename: Amy
authors.initials: A
authors.lastname: Metcalfe
authors.forename: Jeffery
authors.initials: J
authors.lastname: Pollard
authors.forename: Rebecca
authors.initials: R
authors.lastname: Simrose
authors.forename: Gregory
authors.initials: G
authors.lastname: Connors
authors.forename: Donna
authors.initials: D
authors.lastname: Jones
authors.forename: Anne
authors.initials: A
authors.lastname: Roggensack
authors.forename: Richard
authors.initials: R
authors.lastname: Krause
authors.forename: Ian
authors.initials: I
authors.lastname: Lange
mesh_terms: D000465:Algorithms; D001158:Arteries / Q000000981:diagnostic imaging; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D047928:Premature Birth; D011446:Prospective Studies; D011673:Pulsatile Flow; D016216:Ultrasonography, Prenatal; D014599:Uterus / Q000098:blood supply*
chemical_list: D015415:Biomarkers; D011266:Pregnancy-Associated Plasma Protein-A