How long does a nuchal translucency scan take to work for Down syndrome?

The sonographer measures the fluid space at the back of the baby’s neck and checks pregnancy details such as gestational age. The measurement is combined with other information in some screening programmes to estimate the chance of chromosomal conditions, including Down syndrome. It is a screening result, not a diagnosis. A measurement that leads to a higher-chance result does not by itself establish that the baby has Down syndrome.

Ask when and how you will receive the combined result, and whether the scan was completed at the appropriate stage of pregnancy. If the view or measurement is difficult to obtain, the service may explain whether another scan or a different screening option is appropriate. If screening indicates a higher chance, discuss diagnostic testing before making decisions. Read more about [Nuchal Translucency Scan](/treatments/pregnancy-and-birth-care/nuchal-translucency-scan/).

Contact your maternity team if you do not receive the expected result or are unsure what follow-up was recommended. Seek urgent pregnancy care for heavy bleeding, severe abdominal pain, fainting, or fluid leakage; these symptoms are separate from how quickly scan findings are reported.

Ask whether the result is based on the scan alone or combined screening, what your individual result means, and which diagnostic or screening choices are available next.