[Nuchal translucency measurement--non invasive ultrasound screening for fetal abnormalities. Part II]

There is well established association between increased nuchal translucency and chromosomal abnormality.

To investigate a new method of screening for fetal abnormalities on the basis of maternal age and fetal nuchal translucency thickness in the first and second term of pregnancy.

A group of 650 pregnant women from the 10th week of pregnancy until childbirth has been put under examination. Nuchal translucency thickness was measured by transvaginal ultrasound examination according to Nicolaides in the first trimester of pregnancy and by transabdominal ultrasound examination between 15-19th week of pregnancy. Derived risk were then calculated.

There were 8 chromosomal and 1 structural defects. When we used a risk of 1:250 as the cutoff to define a positive result on the screening test, the rate of detection of fetal abnormalities was 100%, with a false positive rate 0.7%.

This study suggests a benefit in combining maternal age-related risk together with NT measurement in the first and second trimester of pregnancy. Such kind of test could also be helpful in twin pregnancies.