Abnormal fetal nasal bone visualization Hypoplastic fetal nasal bone 2022-01-31T14:14:12Z Different studies have used different cut-offs to assess the length of nasal bone. Most data supports use of gestation and ethnicity specific centiles or MoMs. Hypoplastic nasal bone on antenatal ultrasound is one of the soft markers for Down syndrome. This marker can be used to adjust a-priori risk for Down syndrome and offer options for further diagnostic testing to the pregnant woman. Hypoplastic nasal bone can also rarely be a marker for submicroscopic copy number abnormalities and single gene disorders in the fetus. Length of the nasal bone below a predetermined cut-off as seen on antenatal ultrasound using standard imaging techniques.