NT Scan During Pregnancy - A Comprehensive Guide

Pregnancy brings mixed feelings - both negative and positive. Women feel happiness and excitement at the same time as fear and anxiety. Concern about the unborn baby's health triggers anxiety in most cases. Will the baby be born healthy or not? This question creates stress and panic among would-be mothers. Prenatal screening tests like NT scans can put an end to such worries. So, What is an NT scan during pregnancy? Let's dig in.

What is An NT Scan in Pregnancy?

NT or Nuchal Translucency is an ultrasound screening done during the first trimester of pregnancy to check if the baby has conditions like down syndrome and other chromosomal abnormalities. If there is any indication of a risk factor, the doctor will advise further diagnostic tests. Nuchal translucency is the translucent space behind the baby's neck, filled with fluid. If the baby has an abnormality like Down syndrome, Patau syndrome, and Edwards syndrome, more fluid accumulates in the Nuchal Translucency. So, the base of the baby's neck appears larger than usual. The test is not invasive, and the results are not conclusive. Blood tests are carried out to confirm or rule out the risks if there are doubts.

What is the Average Nuchal Measurement?

The average NT measurement is 2.18mm. However, a size of below 3.5 mm is considered normal when the baby measures between 45 and 84 mm. So, an NT measurement of 1.2 mm and 2.9 mm can be regarded as standard. The risk of abnormalities increases when the NT exceeds the usual measurement standards. For example, a baby with 6mm NT is more likely to get chromosomal abnormalities. A blood test is done to confirm the results when the measurements are high. The baby is bigger than the average if the blood tests don't detect any abnormalities.

When are NT Tests done?

The nuchal space remains translucent from the 11th to the 13th week of pregnancy. After 14 weeks, the lymphatic system absorbs the fluid. NT scans can sometimes indicate usual measurement standards, even if the baby has an abnormality. Due to lack of accuracy, the scan is not recommended after 14 weeks.

How is an NT Scan Done During Pregnancy?

It is a non-invasive procedure where a sonographer does the screening and has two alternatives.

The first alternative is a trans-abdomen test. The ultrasound probe is moved over the mother's abdomen, and a gel-like substance is applied to the abdominal skin. This facilitates easy movement of the probe and transmits sound waves. The pictures from the trans-abdomen test are more explicit when the bladder is full. Doctors advise emptying of bladder one hour before the appointment and drinking a litre of water after emptying the bladder.

Another alternative is a trans-vaginal test where a small, lubricated ultrasound probe is inserted into the vagina. Although not painful, it can cause minor discomfort. Some sonographers recommend a trans-vaginal test because the images are more detailed.

In both the alternatives, ultrasound waves create images of the fetus. The sonographer will locate the nuchal fold and measure its thickness. The risk probability is calculated through an equation that involves the nuchal fluid measurement, the mother's age, and the number of weeks of pregnancy. The results are used to assess the risk. The accuracy rate of an NT scan is 75%, and when combined with blood tests, it can go up to 85%.

Why Is An NT Test Done?

Why is an NT scan done during pregnancy? Expectant mothers frequently ask this question. NT screening is generally recommended for all pregnant women and is a part of the detailed prenatal scan they undergo in the first trimester. However, NT Scans are considered essential if the mother is older and has a genetic history of chromosomal abnormalities in the family.

The NT screen helps to confirm the following:

• The pregnancy is not ectopic.
• There is only one baby.
• The heartbeat is good.
• The baby has Down syndrome, Edward's syndrome and Patau syndrome There are problems with the heart and skeletal defects.
• There are other chromosomal abnormalities that the baby is suffering from.

While NT screening is not mandatory, it is often recommended by doctors; this screening goes a long way in decreasing anxiety and uncertainty of pregnancy. Now that the readers know what an NT scan is in pregnancy, they can hopefully go ahead with the test more confidently.

You may also like: What To Expect In Your 7-Week Pregnancy Scan Report? (mylofamily.com)

References:

Colleen de Bellefonds. https://www.whattoexpect.com/pregnancy/pregnancy-health/prenatal-testing-nuchal-translucency-screening/ www.whattoexpect.com

PregnancyBirthBaby Team. Nuchal translucency scan www.pregnancybirthbaby.org.au

Healthline Team. https://www.healthline.com/health/pregnancy/nt-scan#Whats-the-purpose-of-an-NT-scan? www.healthline.com.

Chess Thomas Nuchal translucency (NT) scan .www.babycentre.co.uk