top of page
Chromosome error screening
Every woman is at risk of having a chromosomal defect in her fetus / child.
At our outpatient clinic, we focus on the following by sonographic examination in the 1st trimester:


Mother's age

Trisomy risk 21 

  • increases with mother's age, 

  • decreases with gestational age, as approximately 30% of affected fetuses die between 12 and 40 weeks of gestation.

Risk of trisomy 18 and 13  increases with maternal age and decreases with gestational age. 

Turner syndrome  unrelated to maternal age Triploidia  unrelated to maternal age in live births.

Nuchal translucency (NT)


is an ultrasound image of subcutaneously accumulated fluid in the fetal head in the first trimester of pregnancy.

Possible causes of increased NT include:  

  •   heart defects, 

  • venous congestion in the head and neck, 

  • abnormal composition of the extracellular mass, 

  • lymphatic drainage failure, 

  • fetal anemia 

  • fetal hypoproteinemia, 

  • fetal infection.

Fetal heart rate


Euploid and trisomal fruits.  In physiological pregnancies, the heart rate increases from approximately 110 / min. in week 5 at 170 / min. at week 10 and then gradually decreases to 150 / min. in week 14. In trisomic fetuses we find changes in the frequency of the fetus.

Nasal bone  

Between the 11th and 13th gestational week, the nasal bone is absent in the following cases: 

  • Euploid fruits   1 - 3% 

  • in fetuses with trisomy (21, 18, 13) the nasal bone is not present in 40-60%

Flow in the ductus venosus

The ductus venosus is a short vessel connecting the umbilical vein with the inferior cava vein. 

  • Ductus venosus plays an important role in the preferential supply of fetal blood to the fetal brain. 

  • Approximately 80% of oxygenated blood crosses the placenta through the liver and goes directly to the heart. This blood enters the right atrium and then the left atrium through the foramen ovale. From the left atrium, blood continues to the left ventricle and then to the aorta. 

  • Ductus venosus usually closes a few minutes after birth, in premature babies the closure sometimes takes longer.

Flow disorder in the ductus venosus is related  with increased risk for: 

  • chromosomal abnormalities,  

  •   heart defects,  

  •   fetal death. 

bottom of page