Otaño L, Aiello H, Igarzábal L, Matayoshi T, Gadow E C
Division of Obstetrics and Gynecology, Hospital Italiano de Buenos Aires, Argentine.
Prenat Diagn. 2002 Oct;22(10):930-2. doi: 10.1002/pd.431.
To evaluate the association between absence of nasal bone on ultrasound and Down syndrome in fetuses at 11-14 weeks of pregnancy.
One hundred and ninety-four consecutive fetuses from singleton pregnancies undergoing chorionic villi sampling (CVS) were evaluated by transabdominal ultrasound. A sagittal view of the fetal face was obtained and the absence or presence of nasal bone was recorded and correlated with the fetal karyotype.
A successful view of the fetal profile was possible in 183 of 194 (94%) fetuses. The nasal bone was absent in three of five fetuses with Down syndrome, and in one of 175 (0.6%) chromosomally normal fetuses.
Absence of nasal bone by first trimester ultrasound was significantly associated with Down syndrome. When a proper view of the fetal face was obtained, the nasal bone was visible in more than 99% of karyotypically normal fetuses.
