What is considered a concerning measurement for increased nuchal translucency?

Increased nuchal translucency (NT) is an important marker assessed during the first trimester of pregnancy, specifically during an ultrasound around 11 to 14 weeks gestation. It refers to the fluid collection at the back of a fetus's neck, and an elevated measurement can be indicative of potential chromosomal abnormalities, such as Down syndrome, as well as other congenital defects.

A measurement of 3 mm or more is typically identified as concerning because it significantly increases the risk for associated conditions. While various studies and guidelines may differ slightly, the consensus is that an NT measurement above 3 mm indicates a potential need for further diagnostic evaluation, such as non-invasive prenatal testing (NIPT) or invasive procedures like chorionic villus sampling (CVS) or amniocentesis.

Measuring less than 3 mm, particularly values around 2 mm or less, is generally considered a normal finding and does not carry the same level of risk. Thus, the threshold of 3 mm serves as a pivotal cutoff for increased risk assessment in prenatal screening.