[Combination of screening tests for fetal abnormalities in the first and second pregnancy trimesters]

Screening for fetal abnormalities in the second trimester of pregnancy, based on the concentrations of various markers in serum and maternal age, has become widely used in the past decade. In the first trimester fetal malformations are associated with high values for fetal NT.

We propose a new screening method in which measurements obtained during both trimesters are integrated to provide a single estimate of a woman's risk of having a pregnancy affected by genetic syndrome.

Study groups comprised 775 pregnant women where examinations were done between 11th-14th and 15th-19th pregnancy weeks. Nuchal translucency thickness was measured by ultrasound examination in both trimesters of pregnancy. AFP, -HCG and oestriol were measured by ELISA assays. Derived risks were then calculated.

Eight fetal aneuploidies were diagnosed. When we used a risk of 1:250 as the cutoff to define a positive result on the integrated test, the rate of detection of fetal abnormalities was 100%, with a false positive rate of 0.6%.

Integrated test, which is a combination of the ultrasound examination and the triple test allows to achieve high sensitivity and the decrease in the percentage of false positive results, which leads to the reduction in the number of amniocentesis to be performed.