The 13-week scan is a screening for physical abnormalities.

You can have the 13-week scan from 12+3 to 14+3 weeks of pregnancy. This means from twelve weeks and three days up to and including fourteen weeks and three days. In the Netherlands, you can only opt for the 13-week scan if participating in the scientific IMITAS study. This study is investigating the advantages and disadvantages of the 13-week scan.

More about first-trimester examination for structural physical abnormalities.