First trimester screening
First-trimester screenings take place between 11 and 13 weeks of pregnancy. Their main purpose is to detect abnormalities in the baby’s chromosomes that might cause Down syndrome, Edwards’ syndrome or Patau syndrome. A physician will look at your age, blood and ultrasound to narrow down your baby’s risks of any chromosome defects. There are two parts to first-trimester screenings — a blood test and an ultrasound. These are also often referred to as “nuchal scan” or “nuchal translucency screening.”
What is nuchal translucency screening?
Nuchal translucency screening, also commonly referred to as an NT screening, is a specialized form of ultrasound that is not harmful to you or your baby. All babies have fluid around their necks, but those with extra fluid may have chromosome issues. NT screenings are usually paired with a blood test to provide informative results.
How does NT screening work?
During the NT screening, a sonographer will determine the age of the fetus first. Then he or she will measure the thickness of the nuchal fold. The mother’s age, baby’s age and nuchal fold will help determine the possibility of a chromosome defect. Although the test cannot give a confirmed diagnosis, it can determine the likelihood of any defects.
How is a nuchal scan Performed?
A nuchal scan is done by ultrasound. The ultrasound technician will measure the amount of fluid in the back of the baby’s neck. While all babies have some fluid in the back of their necks, the presence of excess fluid in the back of a baby’s neck can be a symptom of an abnormality.
When should I get an NT Screening?
To ensure the highest level of accuracy, NT screening is performed between 11 and 14 weeks of pregnancy.
How accurate are nuchal scans?
Nuchal scans are screening tests, not diagnostic tests. This means they can be used to assess the risk or likelihood that your baby has an abnormality, but they cannot be used to diagnose a condition. If your nuchal scan detects an abnormality, you will have the option to pursue further diagnostic testing.
What should I do if my nuchal scan comes back positive?
If the test comes back positive, your doctor may recommend diagnostic testing.