Which screening test is commonly performed to check for Down syndrome early in pregnancy?

The first-trimester combined screening is a widely accepted and effective method for evaluating the risk of Down syndrome and other chromosomal abnormalities early in pregnancy. This test typically includes a nuchal translucency ultrasound, which measures the thickness of the fluid at the back of the baby's neck. Increased nuchal translucency can indicate a higher risk of Down syndrome. Additionally, a maternal blood test is performed to measure specific markers, such as pregnancy-associated plasma protein-A (PAPP-A) and free beta-hCG. The results from both the ultrasound and blood tests are used together to calculate a risk score, allowing for early detection and counseling options for expectant parents.

While other tests exist for screening and diagnosing fetal abnormalities, first-trimester combined screening is specifically highlighted for its role in assessing the risk of Down syndrome and is performed within a critical early window in pregnancy. This early identification is vital for expectant parents to make informed decisions and facilitate early intervention if necessary.