Nuchal Translucency Exam = Abdominal Ultrasound + First Trimester Screen Bloodwork

At 12 weeks 6 days pregnant, my Maternal Fetal Medicine doctor scheduled an ultrasound appointment for a Nuchal Translucency (NT) exam. I literally had NO IDEA what a NT exam even was or what to expect during the appointment.

I guess the goal of a NT exam is to measure the nuchal fold thickness AKA the area of tissue at the back of your unborn baby’s neck. Measuring this thickness may help assess the risk for Down Syndrome and other chromosomal abnormalities before the baby is born.

Low Risk Measurements: At 11 weeks: ≤ 2 mm At 13 weeks 6 days: ≤ 2.8 mm

If the measurements are higher, this means there is more fluid than normal in the back of the baby’s neck and there is a higher risk for Down Syndrome, Trisomy 18, Trisomy 13, Turner Syndrome, or Congenital Heart Disease. Your doctor may refer you to a Genetic Counselor for additional testing.

Our ultrasound took about 30 minutes for the ultrasound technician to measure each of our baby’s neck (we’re having twins!). She also spent time monitoring each baby’s heart rate. We really did not get very good pictures of the twins during this ultrasound appointment because (1) I do not think I drank enough water before and (2) the babies were super active and moving all around!

After my ultrasound appointment, I went to get bloodwork to complete my First Trimester Screen. This test includes a human chorionic gonadotrophin (hCG) level and PAPP-A level.

The hCG level is a hormone produced by the placenta during pregnancy. hCG is found in urine / blood around 10 days after conception and is the highest towards the end of the first trimester.

The PAPP-A level, also known as the Pregnancy-associated plasma protein level, is a protein made by the placenta in early pregnancy. Abnormal levels could mean an increased risk for a chromosome defect.

After the Lab receives the results from the bloodwork, you will receive a report with the Nuchal measurements, hCG level, PAPP-A level, and an interpretation of the results AKA “SCREEN POSITIVE” or “SCREEN NEGATIVE”. If the interpretation is a “SCREEN POSITIVE”, it means there is an increased risk for Down Syndrome (1 in 80) and/or another chromosomal abnormality so additional testing may be indicated. If the interpretation is a “SCREEN NEGATIVE”, it means there is no additional risk for Down Syndrome and/or another chromosomal abnormality.

For our test, my hCG was quite elevated (maybe because of the twins) which led to a “SCREEN POSITIVE” so off to a Genetic Consult we go! Stay tuned for What to Expect at a Genetic Consult.