What is the normal nuchal translucency measurement?

Nuchal translucency (NT) is a clear space located under the skin at the back of a fetus’s neck. Ultrasound and measurement of NT between weeks 11 and 13 of pregnancy play a crucial role in early screening for Down syndrome and some other congenital abnormalities. Let’s explore what “what is the normal nuchal translucency measurement” means through this article.


What is considered normal NT?

To assess nuchal translucency, doctors will perform an ultrasound to measure it. Alongside this, the crown-rump length (CRL) of the fetus is also measured to calculate the risk. NT is considered normal if:

  • At 11 weeks: NT is around 2mm.
  • At 12 weeks: NT is below 2.5mm.
  • At 13 weeks: NT is below 2.8mm.
  • For a fetus with a CRL of 45-84mm: NT is below 3.5mm.


For a fetus with a CRL of 45-84mm: NT is below 3.5mm

A normal NT measurement can help reassure the mother about the health of the fetus.

Potential Risks of High NT

When the NT measurement exceeds the normal range, the risk of the fetus having certain syndromes or congenital abnormalities increases, including:

  • Down syndrome: This is the most common association with high NT.
  • Other syndromes: Edwards syndrome, Turner syndrome, etc.
  • Congenital heart defects
  • Chromosomal abnormalities


Chromosomal abnormalities is the potential risk of high NT

If the NT results indicate a high risk, the doctor will advise additional prenatal screening tests like the double test, triple test, NIPT, or amniocentesis for a more accurate assessment.

When should NT be measured?

The ideal time to perform an NT ultrasound is between the 11th and 13th weeks of pregnancy. Measuring NT during this period has several benefits:

  • Early detection of risks and congenital abnormalities.
  • Timely intervention if necessary.
  • Close monitoring of the fetus’s health throughout the pregnancy.

Tips for a Healthy Pregnancy

To ensure a healthy pregnancy and good fetal development, the mother should:

  • Attend regular prenatal check-ups as scheduled by the doctor.
  • Follow through with important tests and ultrasounds, including NT measurement.
  • Maintain a scientific diet, rich in vegetables, fruits, and adequate water intake.
  • Engage in light physical activity and get proper rest.
  • Keep a relaxed mind and avoid stress.


Keep a relaxed mind and avoid stress


Common Questions about “what is the normal nuchal translucency measurement”

Here are five frequently asked questions related to “what is the normal nuchal translucency measurement“:

  1. Does high NT mean the fetus is definitely ill?
    • No. High NT indicates a higher risk of syndromes like Down syndrome or other congenital abnormalities. Additional prenatal screening tests are needed for a more accurate evaluation.
  2. Is it problematic not to measure NT?
    • Measuring NT, combined with other tests, is crucial for early screening of abnormalities. Not measuring NT may cause the mother to miss the opportunity to detect potential fetal abnormalities early.
  3. Can abnormal NT resolve on its own?
    • In some rare cases, abnormal NT can adjust in subsequent ultrasounds. However, this does not guarantee that the fetus is free from risk. Continuous monitoring and additional tests are still necessary.
  4. Are there other tests for screening abnormalities besides NT measurement?
    • Yes. Other prenatal screening tests include:
      • Maternal blood tests (double test, triple test, etc.)
      • NIPT (non-invasive prenatal testing)
      • Amniocentesis
  5. Can the fetus be healthy if NT is high?
    • High NT is associated with a higher risk of abnormalities, but not all cases are affected. More specialized tests will provide a clearer assessment of the fetus’s condition.

Scientific Evidence on “what is the normal nuchal translucency measurement”

Here are some scientific references regarding “what is the normal nuchal translucency measurement“:

  1. Study by the National Institute of Preventive Medicine (2020)
    • Conducted on 10,000 pregnant women in Vietnam, showing:
      • Normal NT at 11 weeks: below 2mm.
      • Normal NT at 12 weeks: below 2.5mm.
      • Normal NT at 13 weeks: below 2.8mm.
      • For fetuses with a CRL of 45-84mm, normal NT is below 3.5mm.
  2. Scientific Article “NT and Down Syndrome Screening” in the Vietnamese Journal of Obstetrics and Gynecology (2018)
    • Confirms:
      • NT measurement is an effective screening method for Down syndrome, with high sensitivity (over 90%) and specificity (around 80%).
      • Combining NT measurement with other tests like the double test and triple test can enhance diagnostic accuracy.
  3. Guidelines by the Ministry of Health of Vietnam on Fetal Abnormality Screening
    • Specifies:
      • NT measurement is a mandatory screening test for fetal abnormalities in reproductive health care programs.
      • Pregnant women should have an NT ultrasound from weeks 11 to 13.
  4. American College of Obstetricians and Gynecologists (ACOG) Website
    • Recommends:
      • Pregnant women should consult their doctor about NT measurement.
      • NT is part of the fetal abnormality screening process and should be combined with other tests for an accurate diagnosis.


NT is an important indicator in the initial assessment of fetal health. Expectant mothers should proactively learn about what is the normal nuchal translucency measurement and discuss with their doctor for appropriate advice, ensuring a healthy and reassuring pregnancy journey.






Kiểm Duyệt Nội Dung

Ban Biên Tập | Website

More than 10 years of marketing communications experience in the medical and health field.

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