Fetal Nasal Bone Length

Median Normal nasal bone lengths :

2.3 (range, 1.5–3.2), mm between 77 and 83 days’ gestational age- 11-12 Weeks
2.6 (range, 1.4–4.2), mm between 84 and 90 days’ gestational age- 12-13 Weeks
2.9 (range, 2.1–3.8) mm between 91 and 98 days’ gestational age - 13-14 Weeks

Absent Nasal Bone High Correlation with Downs