A nuchal fold translucency screening is performed during the first trimester to determine if the fetus is at risk for developing Down Syndrome or another chromosomal abnormality like Trisomy 13 or 18.
Neuchal Fold Translucency
Neuchal fold translucency refers to the thickness of the fluid located at the back of a fetus’s neck that accumulates over the course of the first trimester.
When Is the Test Performed?
The neuchal translucency screening should be performed from 11 weeks to 13 weeks and 6 days of pregnancy.
How Is the Test Performed?
The neuchal translucency screening is an ultrasound of the fetus. The doctor will locate the nuchal fold and take measurements of the thickness of the fluid. The ultrasound is often combined with a blood test.
How Are the Results Calculated?
The mothers age, the baby's gestational age, the measurements from the ultrasound and if available, the blood test results, are all sent to the lab where the level of risk will be determined. The mother's age is included because risk increases as she ages.
What Is a Normal Measurement?
Based on the measurements alone, a normal nuchal thickness level can range from 2 mm to 2.9 mm during weeks 11 to 13. Increased thickness indicates increased risk.