Fetal nasal bone length for various ethnic groups BETA TESTING

Home >  Calculators >  Fetal nasal bone length for various ethnic groups

A hypoplastic (absent or underdeveloped) nasal bone increases the likelihood that a fetus has Down syndrome ,and the likelihood that a fetus has Down syndrome increases as the length of the nasal bone (NB)  decreases [1].

Because normal nasal bone length during the second trimester appears to vary according to race and ethnic background the use of a single fixed cutoff value may be unsuitable for predicting Down syndrome in all populations [2,3,4].  Cusick and colleagues proposed a normal nasal bone length be defined as > 0.7 MoM [2]. Odibo and co-workers found a nasal bone MoM <0.75 to be the best definition of NB hypoplasia in their studies [5] . Has et al., found a nasal bone length less than 5th percentile ,  <0.72 MoM, or BPD:NBL > 12.16 could be  used in the second trimester for diagnosing fetal NB hypoplasia as a means of predicting trisomy 21 because their predictive values are similar at a fixed 5% false-positive rate [6]

The calculator below will give median   nasal bone lengths  for various populations 

Enter   gestational age  weeks  
Enter your measured nasal bone  length   (mm)      



All calculations must be confirmed before use. The suggested results are not a substitute for clinical judgment. Neither nor any other party involved in the preparation or publication of this site shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.

Home | About | Disclaimer | Privacy | Contact

Copyright © 2015 by Focus Information Technology. All rights reserved.