Association between first trimester absence of fetal nasal bone on ultrasound and Down syndrome.
OBJECTIVE
To evaluate the association between absence of nasal bone on ultrasound and Down syndrome in fetuses at 11-14 weeks of pregnancy.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Otaño
L
L
Division of Obstetrics and Gynecology, Hospital Italiano de Buenos Aires, Argentine. lucas.otano@hosptialitaliano.org.ar
Aiello
H
H
Igarzábal
L
L
Matayoshi
T
T
Gadow
E C
EC
D000328:Adult; D000782:Aneuploidy; D015415:Biomarkers; D018568:Crown-Rump Length; D004314:Down Syndrome / Q000000981:diagnostic imaging*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007621:Karyotyping; D008423:Maternal Age; D009295:Nasal Bone / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000196:embryology*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D018566:Pregnancy, High-Risk; D016216:Ultrasonography, Prenatal
D015415:Biomarkers