First-Trimester Nuchal Translucency Screening to Detect Down Syndrome

Trisomy 21 (or Down syndrome) is the most frequently observed chromosomal anomaly among live births today. The risk of Down syndrome significantly increases with age; however, the most affected babies are born to women younger than 35 years. Thus, approximately 80% of babies diagnosed with trisomy 21 are born to mothers who are not historically categorized as “at-risk” for advanced maternal age. Combining nuchal translucency measurement with maternal biochemical markers has led to a multitude of screening options available and results in identifying trisomy 21 earlier in pregnancy. However, it is important to continue to emphasize access to all levels of prenatal care, as well as respect the family's decision-making abilities. Informed choice and counseling are pertinent whenever the screening is performed.