Understanding Early Pregnancy Scans
Early pregnancy involves several important ultrasound scans to monitor fetal health and development. Two common scans during the first trimester are the viability scan and the nuchal translucency (NT) scan. Although both are ultrasound procedures, they serve different purposes and are performed at different stages.
What is a Viability Scan?
A viability scan is usually performed between 6 to 9 weeks of pregnancy. Its primary goals include:
- Confirming the presence of an intrauterine pregnancy
- Detecting a fetal heartbeat
- Estimating the gestational age of the embryo
- Checking for multiple pregnancies (twins or more)
- Identifying early pregnancy complications such as ectopic pregnancy or miscarriage risk
This scan reassures parents that the pregnancy is developing normally in the early stages.
What is the NT Scan?
The Nuchal Translucency (NT) scan is a screening test performed between 11 and 13 weeks of pregnancy. It measures the thickness of the clear fluid-filled space at the back of the baby’s neck called the nuchal translucency.
An increased NT measurement can indicate a higher risk for certain chromosomal abnormalities, including:
- Down syndrome (Trisomy 21)
- Edwards syndrome (Trisomy 18)
- Patau syndrome (Trisomy 13)
The NT scan is usually combined with blood tests to provide a risk assessment for these conditions.
Key Differences Between Viability Scan and NT Scan
|
Feature |
Viability Scan |
NT Scan |
|
Timing |
6 – 9 weeks |
11 – 13 weeks |
|
Purpose |
Confirm pregnancy and heartbeat |
Screen for chromosomal abnormalities |
|
What it measures |
Presence of embryo and heartbeat |
Thickness of nuchal translucency |
|
Additional use |
Check for multiples, early risks |
Combined with blood tests for risk score |
Why Are Both Scans Important?
- The viability scan provides early confirmation and peace of mind that the pregnancy is progressing normally.
- The NT scan offers valuable information about genetic risks that help parents make informed decisions about further testing and pregnancy management.
Both scans are non-invasive, safe, and vital parts of comprehensive prenatal care.
Understanding the difference between the viability scan and NT scan can help expectant parents navigate early pregnancy with confidence. Always follow your healthcare provider’s advice on when to schedule these important ultrasounds.