Key Takeaways
- The NT/NB scan, performed between 11-14 weeks of pregnancy, is a crucial ultrasound examination that assesses the foetus’s health and development.
- It measures the nuchal translucency and evaluates the presence of the nasal bone, which can indicate the risk of chromosomal abnormalities.
- The scan also assesses blood flow in the ductus venosus and tricuspid valve.
- With an accuracy rate of 70-75% alone and 85% when combined with blood tests, the NT/NB scan enables early detection, risk stratification, and informed decision-making, providing peace of mind for expectant parents.
As an expecting parent, you might come across various medical terms and procedures that can seem overwhelming at first. One such important test is the NT/NB scan, also known as the nuchal translucency scan. This specialised ultrasound examination, typically performed between the 11th and 14th weeks of pregnancy, plays a crucial role in assessing your baby’s health and development. In this article, we’ll delve into the details of the NT/NB scan, its purpose, procedure, and significance in your pregnancy journey.
What is the Purpose of the NT/NB Scan?
The primary goal of the NT/NB scan is to screen for potential chromosomal abnormalities in your developing foetus, particularly Down syndrome, Edwards syndrome, and Patau syndrome. The scan focuses on two key factors:
- Nuchal Translucency: It is a measurement of the fluid at the back of your baby’s neck. A larger measurement may indicate a higher risk of chromosomal abnormalities.
- Nasal Bone Development: The presence or absence of a nasal bone is assessed during the scan. A well-developed nasal bone may indicate a lower risk of chromosomal abnormalities.
By evaluating these factors, the NT/NB scan provides valuable information about your baby’s health and helps identify any potential concerns early on.
The NT/NB scan, performed between the 11th and 14th weeks of pregnancy, is a crucial prenatal screening test that assesses the risk of chromosomal abnormalities like Down syndrome. This non-invasive ultrasound examination measures the thickness of the nuchal translucency and evaluates the presence of the nasal bone, providing valuable insights into the baby’s health.
What is the NT/NB Scan Procedure?
The NT/NB scan is a non-invasive ultrasound examination that can be performed in two ways, depending on the clarity of the images and your baby’s position:
- Abdominal Ultrasound: The technician uses a transducer on your abdomen to capture images and measurements of your baby. This method is generally preferred but may require a full bladder to obtain clear images.
- Transvaginal Ultrasound: A well-lubricated ultrasound probe is inserted into your vagina to scan your uterus. This method is used when the abdominal ultrasound is not clear or when your baby is in a position that makes abdominal scanning difficult.
The procedure typically takes between 20 to 30 minutes and is painless, although the transvaginal method may cause some discomfort.
Why is the NT/NB Scan Essential for Your Pregnancy?
The NT/NB scan plays a vital role in your prenatal care for several reasons:
- Early detection of chromosomal abnormalities: It provides an early indication of the risk of chromosomal abnormalities, allowing you to make informed decisions about further testing and potential interventions.
- Identification of structural problems: The scan can identify structural issues such as spina bifida, skeletal defects, and heart malformations.
- More precise delivery date estimation: It helps in estimating a more accurate due date for your baby’s arrival.
- Assessment of pregnancy failure risk: Early detection of any concerns for pregnancy failure.
- Identification of multiple foetuses: It can determine if you are carrying more than one baby.
Normal Range and Timing of the NT/NB Scan
The normal range for the nuchal translucency measurement is typically less than 3.5 mm. Here are some general guidelines:
|
Measurement Range |
Interpretation |
|---|---|
|
Less than 3.5 mm |
Normal range |
|
3.5 mm to 6 mm |
Borderline |
|
6 mm or higher |
Elevated risk |
It’s important to note that the NT/NB scan is usually performed between the 11th and 14th weeks of pregnancy. This timeframe is critical because the clear space at the back of your baby’s neck begins to close up after 15 weeks, making it essential to conduct the scan before this period.
Cost of the NT/NB Scan in India:
The cost of an NT/NB scan can vary depending on your location, hospital, and doctor. In India, the cost typically ranges from ₹1,500 to ₹5,000, although this can vary widely. It’s best to check with your doctor or insurance company to understand the specific costs involved in your case.
Preparing for the NT/NB Scan:
To ensure the best possible results from your NT/NB scan, there are a few things you can do to prepare:
- Schedule a blood test: It is recommended to have blood drawn 48 hours prior to the scan. The results will be combined with the ultrasound measurements for a more accurate risk assessment.
- Maintain a full bladder: If you’re having an abdominal ultrasound, a full bladder may be required to obtain clear images. Your doctor will guide you on how much water to drink and when to drink it before the scan.
By following these simple steps, you can help your doctor obtain the most accurate measurements and assessment during your NT/NB scan.
Alternatives to the NT/NB Scan
While the NT/NB scan is a highly effective screening tool, there are alternatives available for women who prefer or require additional testing:
- Non-Invasive Prenatal Testing (NIPT): Also known as cell-free DNA testing (cfDNA), this test analyzes the DNA present in the mother’s blood to detect chromosomal abnormalities. NIPT is a highly accurate screening method that can be performed as early as 10 weeks into the pregnancy.
- Chorionic Villus Sampling (CVS): This diagnostic test involves removing a small sample of the placenta for genetic testing. CVS is typically performed between 10 and 13 weeks of pregnancy and can provide definitive information about chromosomal abnormalities.
- Amniocentesis: Another diagnostic test, amniocentesis involves removing a small amount of amniotic fluid for genetic testing. This test is usually performed between 15 and 20 weeks of pregnancy and can provide conclusive results about chromosomal abnormalities.
Your doctor can help you determine which tests are most appropriate for your individual situation and provide guidance on the benefits and risks associated with each option.
Conclusion
The NT/NB scan is a valuable prenatal screening tool that provides critical information about the health and development of your baby during the first trimester of pregnancy. By measuring the nuchal translucency and assessing the presence of the nasal bone, this non-invasive ultrasound examination can help identify potential chromosomal abnormalities and other structural issues early on. The scan is safe, highly accurate, and plays a crucial role in ensuring the best possible care for you and your growing baby.
Word from the Expert:
The NT/NB scan is a remarkable tool that allows us to assess the health and development of the foetus during the first trimester of pregnancy. NT/NB scans help detect potential chromosomal abnormalities early in pregnancy, allowing parents to make informed decisions about their pregnancy care. As a doctor, I highly recommend the NT/NB scan to all my patients as an essential part of their prenatal care plan. ~ Dr. Anupam Kumari
