What is an NT Scan during Pregnancy?
Verified by: Dr. Shreyas Cadabam
The experience of pregnancy is full of excitement and anticipation, though it naturally brings many questions and concerns. One of the most important diagnostic tools used during early pregnancy is the nuchal translucency (NT) scan.
This blog will guide you through everything you need to know about the NT scan in pregnancy, including its purpose, procedure, and what the results could mean for you and your baby.
Overview of NT Scan
An NT scan, or nuchal translucency scan, is an important early pregnancy test that checks for potential chromosomal issues. Understanding what this scan involves can offer reassurance and helpful information for expecting parents.
Defining Nuchal Translucency (NT) Scan
The NT scan is an ultrasound examination conducted between 11 – 14 weeks of pregnancy. Its primary purpose is to measure the nuchal translucency, the fluid-filled space at the back of the fetus’s neck.
By measuring this, we can assess the risk for chromosomal abnormalities, including Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13). The scan also aids in detecting other potential issues, such as heart defects.
What’s the purpose of an NT scan?
An NT scan is a common first-trimester screening test that measures the nuchal translucency, a fluid-filled space at the back of the fetus’s neck. While it’s normal for a fetus to have some fluid here, excess fluid can indicate chromosomal abnormalities like Down syndrome, Patau syndrome, or Edwards syndrome.
Our body cells contain a nucleus that holds genetic material, usually organised into 23 pairs of chromosomes inherited from both parents. The presence of an extra chromosome 21 in individuals with Down syndrome results in developmental delays and distinct physical traits, including a smaller stature, upward-slanting eyes, and low muscle tone.
This condition occurs in 1 out of every 700 newborns in the United States, making it one of the most common genetic conditions.
Patau syndrome and Edwards syndrome are rarer and more severe chromosome abnormalities, often resulting in fatal outcomes within the first year of life.
How NT Scan Works
During the NT scan, an ultrasound transducer is placed on the mother’s abdomen to capture images of the fetus. Measuring the thickness of the nuchal translucency is the primary function of the NT scan.
A higher-than-normal measurement may indicate an increased risk of chromosomal abnormalities. The scan is typically combined with a blood test to enhance the accuracy of the screening.
Reasons to Have This Scan
Expecting parents often choose to undergo the NT scan to gain early insights into their baby’s health. The scan provides valuable information that can help in making informed decisions about further testing options, for instance, chorionic villus sampling (CVS) or amniocentesis, and planning for any necessary medical interventions during the pregnancy.
Early detection of potential abnormalities allows parents to prepare emotionally and medically for any necessary interventions.
When and Why to Get an NT Scan
Getting an NT (Nuchal Translucency) scan is an important part of prenatal care, providing valuable insights into the health and development of your baby. Understanding the timing and reasons for this scan can help expectant parents make informed decisions about their pregnancy journey.
Ideal Timing for NT Scan
The NT scan is ideally performed between 11 and 14 weeks of pregnancy when the nuchal translucency is most visible and measurable. Performing the scan too early or too late may result in inaccurate measurements, reducing the effectiveness of the screening.
NT Scan and Chromosomal Abnormalities
The NT scan is instrumental in assessing the risk of chromosomal abnormalities. A higher nuchal translucency measurement can indicate a higher probability of conditions like Down syndrome.
However, it is essential to understand that the NT scan is a screening test, not a diagnostic tool. Abnormal results may warrant further diagnostic testing, such as chorionic villus sampling (CVS) or amniocentesis.
The NT Scan Procedure
The NT (Nuchal Translucency) scan is a vital part of prenatal screening that helps assess the risk of chromosomal abnormalities in the developing fetus. Understanding the steps involved in this procedure can help parents feel more prepared and informed about what to expect during the scan.
Preparing for the Scan
Preparation for the NT scan is relatively simple. It is recommended to have a full bladder during the scan, as it can improve the quality of the ultrasound images. Drinking water before the appointment can help achieve this. Wearing comfortable clothing that allows easy access to the abdomen is also advisable.
What to Expect During the Scan
During the NT scan, the ultrasound technician will apply a gel to the mother’s abdomen and use a transducer to capture images of the fetus. The procedure is painless and typically takes about 20 to 40 minutes.
The technician will measure the thickness of the nuchal translucency and may also check for the presence of the nasal bone, which can further refine the risk assessment for chromosomal abnormalities. Throughout the scan, the expectant parents may be able to see their baby on the monitor, providing a first glimpse of their developing child. The results of the scan will be discussed with the parents, often in combination with blood test results, to provide a comprehensive risk assessment.
Interpreting NT Scan Results
Interpreting the results of an NT (Nuchal Translucency) scan is crucial for understanding the potential risks of chromosomal abnormalities in the developing fetus.
This process involves analysing specific measurements and combining them with other factors to provide a comprehensive risk assessment.
Knowing how to interpret these results can help parents make informed decisions about further testing and their pregnancy journey.
Understanding the Measurements
The results of the NT scan are usually available immediately after the procedure. The key measurement is the thickness of the nuchal translucency.
A measurement of less than 3.5 millimetres is generally considered normal, while a measurement greater than 3.5 millimetres may indicate an increased risk of chromosomal abnormalities.
The results are often combined with the mother’s age and the results of a blood test to calculate an overall risk assessment. This combined approach helps in providing a more accurate evaluation of the baby’s risk for conditions such as Down syndrome, trisomy 18, and other chromosomal abnormalities.
What Normal and Abnormal Results Mean
Normal NT scan results suggest a lower risk of chromosomal abnormalities, but they do not guarantee that the baby is free from all potential issues. It’s essential to understand that the NT scan is a screening tool, not a diagnostic test.
Even with normal results, there may still be a small risk of abnormalities or other conditions that are not detectable through this scan.
Abnormal results indicate a higher risk and may prompt further diagnostic testing. If the nuchal translucency measurement exceeds 3.5 millimetres, the healthcare provider could advise additional tests such as chorionic villus sampling (CVS) or amniocentesis.
These diagnostic tests can provide more definitive information about the baby’s chromosomal status. It is important to remember that an abnormal NT scan does not confirm a diagnosis; it only indicates the need for additional investigation.
It is important for parents to discuss the results with their healthcare provider to gain a clear understanding and decide on the appropriate next steps in their prenatal care.
Follow-Up After NT Scan
Following an NT (Nuchal Translucency) scan, understanding the next steps is crucial for expectant parents, especially if the results indicate a higher risk of chromosomal abnormalities.
The follow-up process involves additional testing, counselling, and support to ensure that parents are well-informed and supported throughout their pregnancy journey.
Additional Testing and Diagnosis
If the NT scan results indicate a higher risk of chromosomal abnormalities, your healthcare provider may recommend additional testing. Here are some key points about these diagnostic tests:
Chorionic Villus Sampling (CVS):
- Timing: Typically performed between 10 and 13 weeks of pregnancy.
- Procedure: Involves taking a small sample of placental tissue.
- Purpose: Provides more definitive information about chromosomal abnormalities.
- Accuracy: High degree of accuracy in detecting chromosomal abnormalities.
- Risks: Carries a small risk of complications, including miscarriage.
Amniocentesis:
- Timing: Usually performed between 15 and 20 weeks of pregnancy.
- Procedure: Requires drawing a small amount of amniotic fluid.
- Purpose: Provides more definitive information about chromosomal abnormalities.
- Accuracy: High degree of accuracy in detecting chromosomal abnormalities.
- Risks: Carries a small risk of complications, including miscarriage.
Consultation with Healthcare Provider: Your healthcare provider will discuss the risks and benefits of procedures like CVS and amniocentesis, helping parents understand the implications and make an informed decision about additional testing.
This consultation is crucial for weighing the accuracy of these tests against their small risk of complications, ensuring that parents have all the necessary information to choose the best course of action for their pregnancy.
Counselling and Support
Receiving abnormal NT scan results can be emotionally difficult for expectant parents. It is essential to seek counselling and support from healthcare professionals, genetic counsellors, and support groups.
They can provide valuable information, guidance, and emotional support to help parents navigate the next steps in their pregnancy journey. Genetic counsellors can offer detailed explanations about the potential implications of the results and the available testing options, helping parents understand the chances of specific conditions.
Support groups and counselling services can provide a safe space for parents to express their feelings, share experiences, and receive encouragement from others who have faced similar situations. Utilising these resources can reduce anxiety and empower parents to make the best decisions for their family’s health and well-being.
Embrace Pregnancy Health with Cadabams Diagnostics
At Cadabams Diagnostics, we understand the importance of comprehensive prenatal care. Our team of experienced healthcare professionals is dedicated to providing expecting parents with the support and information they need. From NT scans to follow-up testing and counselling, we are here to ensure a healthy and informed pregnancy journey.
Make your pregnancy health a priority with Cadabams Diagnostics, where your well-being and your baby’s health are our top focus. Schedule your NT scan with us today and take the first step towards a healthy pregnancy. Our test packages are designed to cover all aspects of prenatal care, ensuring you have access to the best possible support and diagnostics.
Contact us now to book an appointment and experience the exceptional care and support that Cadabam's Diagnostics offers.