title: First-trimester nasal bone evaluation for aneuploidy in the general population.
abstract: OBJECTIVE
  To evaluate the role of fetal nasal bone imaging at 10 3/7 to 13 6/7 weeks as a screening tool for aneuploidy, in a prospective multicenter trial.
  
  
  METHODS
  Unselected patients from the general population with viable singleton pregnancies at 10 3/7 to 13 6/7 weeks were recruited at 15 U.S. centers. All had screening with nuchal translucency (NT) ultrasound by specially trained sonographers. In the last 8 months of this trial, first trimester nasal bone evaluation was added to the screening protocol. Nasal bones were described as present, absent, or unable to determine.
  
  
  RESULTS
  A total of 38,189 patients completed first trimester NT screening, of whom 6,324 also underwent nasal bone sonography. An acceptable nasal image was obtained in 4,801 cases (76%), with nasal bones described as present in 4,779 (99.5%), and absent in 22 (0.5%). There were 11 identified cases of trisomy-21 in the population of 6,324 patients. In 9 of the 11 cases (82%) the nasal bones were described as present, and 2 cases were described as unable to determine. The only other aneuploidies were 2 cases of trisomy-18, in 1 of which the nasal bones were described as absent, and in 1 present. Absence of nasal bones had sensitivity for aneuploidy of 7.7%, false-positive rate 0.3%, and positive predictive value 4.5%.
  
  
  CONCLUSIONS
  First-trimester nasal bone evaluation was not a useful test for population screening for trisomy-21 and added little to first-trimester NT screening. The difficulty in performing first-trimester nasal bone sonography consistently, in the general population setting, will significantly limit the usefulness of this aneuploidy screening technique.
authors.affiliation: Columbia University College of Physicians and Surgeons, New York, New York, USA. fdm9@columbia.edu
authors.forename: Fergal D
authors.initials: FD
authors.lastname: Malone
authors.forename: Robert H
authors.initials: RH
authors.lastname: Ball
authors.forename: David A
authors.initials: DA
authors.lastname: Nyberg
authors.forename: Christine H
authors.initials: CH
authors.lastname: Comstock
authors.forename: George
authors.initials: G
authors.lastname: Saade
authors.forename: Richard L
authors.initials: RL
authors.lastname: Berkowitz
authors.forename: Lorraine
authors.initials: L
authors.lastname: Dugoff
authors.forename: Sabrina D
authors.initials: SD
authors.lastname: Craigo
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Carr
authors.forename: Honor M
authors.initials: HM
authors.lastname: Wolfe
authors.forename: Tara
authors.initials: T
authors.lastname: Tripp
authors.forename: Mary E
authors.initials: ME
authors.lastname: D'Alton
mesh_terms: D000782:Aneuploidy; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D005333:Fetus / Q000002:abnormalities*; D006801:Humans; D015337:Multicenter Studies as Topic; D009295:Nasal Bone / Q000000981:diagnostic imaging* / Q000196:embryology* / Q000473:pathology; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal