Among various pregnancy scans, the Nuchal Translucency scan, though not compulsory, can be one of the most important scans in the first trimester. Did your doctor ask you to take a Nuchal Translucency scan? Wondering what it is for and why it is so important? Read on, we will tell you all about it.
A Nuchal Translucency (NT) scan is an ultrasound taken in the first trimester of pregnancy. It helps to examine the space behind the baby's neck, known as the nuchal fold.
All babies have a little fluid behind their necks, but if they have any chromosomal or genetic condition, there will be more fluid buildup. A buildup of fluid in this area suggests the possibility of the baby developing Down's Syndrome, Patau Syndrome, or Edward's Syndrome. Higher fluid buildup in the nuchal fold indicates a higher risk for congenital heart issues.
The NT scan is a screening test, meaning it can only screen the baby and check for issues. The scan measures the fluid in the nuchal fold in millimetres. The measurement helps doctors or health care providers determine the possibility of the baby developing complications.
During the NT scan, the ultrasound will also check the baby's anatomical structure. The presence of anomalies during the scan increases the risk of the baby developing genetic or structural issues.
The NT scan is generally taken between weeks 11 and 13 of pregnancy. The baby is roughly 45 – 85 millimetres long (crown to rump). Taking this scan after 13 weeks may not give accurate results as the body tends to reabsorb the fluid around the 14th week of pregnancy.
The scan is optional but is highly recommended by doctors and midwives. All pregnant women can take this scan until they are between the 11th and 13th weeks of pregnancy. If you have a family history of Down's syndrome, Patau Syndrome, or Edward's syndrome, it is advisable to take this scan without any delay.
The NT scan sounds complicated, but is a very simple scan. It can be done abdominally or vaginally. After applying the ultrasound gel, the technician or doctor will use the transducer to examine the baby closely. If the baby's neck and the area behind it is not visible enough to measure the fluid, the doctor will opt for a vaginal ultrasound.
The results and readings of various scans taken during the first trimester and the measurements from the nuchal translucency scan are combined to determine if the baby is at risk of developing any congenital issues.
In most cases, a blood test is also taken along with the scan for more accuracy. The maternal age and the baby's nasal bone are two of the most common factors considered during this NT scan. In many cases, the increase in NT may not be due to any chromosomal or genetic condition. So, additional tests are always taken to confirm a diagnosis.
The Nuchal Translucency scan normal range will vary from institute to institute. In most cases, if the NT records more than 3 millimetres, further tests will be taken. Many centres will also suggest genetic counselling for better assessment.
An abnormal NT scan does not mean your baby has Down's Syndrome or other complications. It only indicates a higher risk of the baby developing those conditions. More prenatal testing will help re-evaluate and diagnose the condition with more accuracy.
The NT scan is a low-risk screening that will not harm the baby or the mother. It has an accuracy of about 70% for trisomy 21 and Down's Syndrome. The NT screening's accuracy increases to 95% when combined with the first-trimester blood tests.
If the NT scan shows any indication of a risk, the doctor will perform further tests. A Chorionic Villus Sampling or Amniocentesis test can help diagnose possible conditions. They will also perform a fetal echocardiogram, as an abnormal NT can also indicate fetal heart defects.
Fetal abnormalities or even an “increased risk” of abnormalities can be very disturbing news for expecting parents. Remember, the NT scan is highly accurate but is not 100% accurate. Take all the necessary or recommended tests before confirming a diagnosis. Seek counselling to help you decide the next course of action.
The nuchal translucency ultrasound measures the fluid build-up behind the fetus' neck, known as the nuchal fold. If more than the normal amount of fluid is measured, it indicates genetic or structural issues in the baby, including conditions like Down's Syndrome or Trisomy 21.
No, it is not painful. In most cases, it is done externally by applying a gel on the abdomen and using a transducer. In some cases, it is done internally through the vaginal opening, which can be uncomfortable.
The normal nuchal translucency scan range is around 3 millimeters. However, the range can vary slightly from institute to institute, so ensure you refer to the range given in your report.
The scan at 12 weeks of pregnancy is known as the dating scan. It aims to determine the age of the fetus and calculate the expected delivery date. The Nuchal translucency scan is also taken around the 12th week, and both can be done together. A dating scan is necessary to estimate the delivery date. However, an NT scan is optional.
