OBJECTIVE: To evaluate the utility of determining the presence/absence of nasal bone in a low-risk fetal population. METHODS: Prospective study of the presence/absence of nasal bone among 1800 consecutive unselected fetuses, with complete follow-up of results. RESULTS: An adequate sonographic evaluation of nasal bone was obtained in 1682 (93.44%) of the fetuses. Nasal bone was considered absent in 19 (1.06%) of 1790 fetuses with a normal karyotype and in 2 (28.57%) of the seven recorded cases of Down syndrome (DS). The overall first-trimester sensitivity for DS to the absence of nasal bone was two of the six cases (33.3%) and the false-positive rate was 1.13%. The positive predictive value for DS of the absence of nasal bone was 2/21 (9.52%). CONCLUSIONS: In a low-risk population, the evaluation of the presence/absence of nasal bone in DS screening during the first trimester has a low sensitivity. First-trimester assessment of the nasal bone in population screening may play a lesser role than in the re-evaluation of high-risk pregnancies. Copyright 2006 John Wiley & Sons, Ltd.
OBJECTIVE: To evaluate the utility of determining the presence/absence of nasal bone in a low-risk fetal population. METHODS: Prospective study of the presence/absence of nasal bone among 1800 consecutive unselected fetuses, with complete follow-up of results. RESULTS: An adequate sonographic evaluation of nasal bone was obtained in 1682 (93.44%) of the fetuses. Nasal bone was considered absent in 19 (1.06%) of 1790 fetuses with a normal karyotype and in 2 (28.57%) of the seven recorded cases of Down syndrome (DS). The overall first-trimester sensitivity for DS to the absence of nasal bone was two of the six cases (33.3%) and the false-positive rate was 1.13%. The positive predictive value for DS of the absence of nasal bone was 2/21 (9.52%). CONCLUSIONS: In a low-risk population, the evaluation of the presence/absence of nasal bone in DS screening during the first trimester has a low sensitivity. First-trimester assessment of the nasal bone in population screening may play a lesser role than in the re-evaluation of high-risk pregnancies. Copyright 2006 John Wiley & Sons, Ltd.
Authors: S Kate Alldred; Yemisi Takwoingi; Boliang Guo; Mary Pennant; Jonathan J Deeks; James P Neilson; Zarko Alfirevic Journal: Cochrane Database Syst Rev Date: 2017-03-15