Nuchal Translucency (NT) Scan and Double Marker Test

The nuchal translucency (NT) scan and double marker test are both screening tests used in pregnancy to assess the risk of chromosomal abnormalities such as Down syndrome (trisomy 21), trisomy 18, and trisomy 13 in the fetus.

Nuchal Translucency (NT) Scan:

This specific ultrasound is performed between weeks 11 and 13 of pregnancy. The nuchal translucency, or clean space at the back of the baby's neck, is measured in thickness during this scan. There may be an association between thickness and the possibility of chromosomal abnormalities. For a more accurate assessment of the risk, the NT scan is frequently combined with maternal blood testing, or double marker tests.

Double Marker Test:

The double marker test, also referred to as the first trimester screening test, detects human chorionic gonadotropin (hCG) and pregnancy-associated plasma protein-A (PAPP-A) in the mother's blood. An higher risk of chromosomal abnormalities may be indicated by abnormal levels of these substances. Usually, this test is conducted between weeks Eleven and thirteen of pregnancy.

Both the NT scan and the double marker test are non-invasive and do not pose any risk to the fetus. It's crucial to remember that these are screening tests, not diagnostic tests. Additional diagnostic procedures like chorionic villus sampling (CVS) or amniocentesis may be advised to confirm the diagnosis if the results point to a high risk.