Interpretation of Mixture model in NT

Interpretation of Mixture model in NT

1- The distribution in which NT increases with CRL:

 is the same for chromosomally abnormal and euploid fetuses but the proportion that follows this distribution is :

- - large in the euploid group (about 95%) 

- - and small in the abnormal group being about 5%, 30%, 15% and 20% for trisomies 21, 18, 13 and Turner syndrome, respectively.

2- The distribution in which NT does not change with CRL :

is firstly, small for euploid fetuses and large for the abnormal group 

and secondly, the median NT is different, 

- - being 2.0 mm for the euploid group 

- - and 3.4 mm  for trisomies 21,

- -  5.5 mm  for trisomies 18, 

- - 4.0 mm  for trisomies 13,

- - and 9.2 mm for Turner syndrome.