11-13 week antenatal scan

Last revised by Joshua Yap on 25 Jan 2023

11-13 week antenatal (nuchal translucency) scan is considered a routine investigation advised for fetal well-being as well as for early screening in pregnancy (see antenatal screening).

It includes multiple components and is highly dependent on the operator. Traditionally three factors are used to calculate the risk of trisomies:

Additional markers increase the detection rate and reduce false-positive rates:

Combining these factors with blood tests (i.e. dual marker) has been reported to achieve a nearly 95% detection rate for trisomies.

Apart from the screening protocol, early detection of major anomalies may be possible, and the checklist must include the following conditions:

See also

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Case 1: crown rump length (CRL)
    Drag here to reorder.
  • Case 2: nuchal translucency
    Drag here to reorder.
  • Case 3: fetal heart rate
    Drag here to reorder.
  • Case 4: absent nasal bone
    Drag here to reorder.
  • Case 5: ductus venosus flow (normal)
    Drag here to reorder.
  • Case 6
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.