title: Improved diagnostic accuracy by using secondary ultrasound markers in the first-trimester screening for trisomies 21, 18 and 13 and Turner syndrome.
abstract: OBJECTIVE
  The aim of this study was to examine the effectiveness of a combination of parameters at first-trimester screening for fetal aneuploidies, including ultrasound assessment of the nasal bone (NB), blood flow in the ductus venosus (DV) and flow across the tricuspid valve.
  
  
  METHODS
  Screening for aneuploidy was carried out in 4172 singleton pregnancies between January 2006 and December 2010. Diagnostic accuracy of combined screening [inclusive of maternal age, fetal nuchal translucency (NT) thickness and maternal serum free beta-human chorionic gonadotropin and pregnancy-associated plasma protein A] and of secondary ultrasound markers [NB, tricuspid regurgitation (TR) and Doppler studies of the DV] obtained at the same visit was assessed using the receiver operating characteristic (ROC) curve analysis.
  
  
  RESULTS
  The individual areas under the ROC curves of NT, NB, DV or TR ranged between 0.7 and 0.8, representing acceptable discrimination. The area under the ROC curve of combined first-trimester screening was 0.87, whereas the addition of secondary ultrasound markers increased the area under the curve to 0.92, which represents excellent discrimination. At a risk cutoff of 1 : 275, the detection rate for aneuploidy increased from 87% to 92% (z statistic = 1.78, P = 0.076), and the false positive rate decreased from 5.3% to 4.8%.
  
  
  CONCLUSIONS
  The addition of secondary ultrasound markers (NB, DV and TR) to combined first-trimester screening showed a tendency toward improved accuracy of the screening.
authors.affiliation: Obstetric/Gynecology Clinic Narodni Front, University of Belgrade, Belgrade, Serbia. orlicmail@yahoo.com
authors.forename: Natasa
authors.initials: N
authors.lastname: Karadzov-Orlic
authors.forename: Amira
authors.initials: A
authors.lastname: Egic
authors.forename: Zagorka
authors.initials: Z
authors.lastname: Milovanovic
authors.forename: Maja
authors.initials: M
authors.lastname: Marinkovic
authors.forename: Barbara
authors.initials: B
authors.lastname: Damnjanovic-Pazin
authors.forename: Relja
authors.initials: R
authors.lastname: Lukic
authors.forename: Ivana
authors.initials: I
authors.lastname: Joksic
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Curkovic
authors.forename: Zeljko
authors.initials: Z
authors.lastname: Mikovic
mesh_terms: D000328:Adult; D000782:Aneuploidy; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D025063:Chromosome Disorders / Q000175:diagnosis*; D002882:Chromosomes, Human, Pair 13; D002887:Chromosomes, Human, Pair 18; D003326:Coronary Circulation; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008423:Maternal Age; D009295:Nasal Bone / Q000000981:diagnostic imaging; D048208:Nuchal Translucency Measurement; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis; D012189:Retrospective Studies; D014261:Tricuspid Valve / Q000000981:diagnostic imaging; D014262:Tricuspid Valve Insufficiency / Q000000981:diagnostic imaging; D014314:Trisomy / Q000175:diagnosis*; D000073839:Trisomy 13 Syndrome; D014424:Turner Syndrome / Q000175:diagnosis*; D016216:Ultrasonography, Prenatal / Q000379:methods*; D014471:Umbilical Veins / Q000000981:diagnostic imaging*
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A