What is it?

The 12-week ultrasound is important. At this point, your baby's structure is completed. Your gynaecologist will see:

  • A beating heart
  • A closed skull
  • Two brain halves
  • A closed abdomen
  • Four normal limbs
  • And a nuchal fold of less than 3 mm.

The nuchal fold is a small collection of fluid under the skin of the neck in all embryos that is only present between week 11 and 14 of a pregnancy. The fluid usually disappears after 14 weeks of pregnancy. This can be clearly seen on an ultrasound scan. The thickness of the nuchal fold shows us whether there is an increased risk of an abnormality in the baby:

  • A normal nuchal fold (< 3 mm) means a substantially reduced risk of an abnormality in the baby.
  • Increased thickness of the nuchal fold (> 3 mm) does not necessarily mean that the baby has an abnormality. It does mean that there is an increased risk of an abnormality, both chromosomal and other abnormalities. Careful examination is always recommended.

If abnormalities are still seen at the 12-week ultrasound (including a nuchal fold of more than 3 mm), a NIPT is not worthwhile. In this case, more extensive tests are needed, such as an amniocentesis or a follicle puncture. This order is essential: first the 12-week ultrasound, then the NIPT.

Examples of abnormalities sometimes seen at the 12-week ultrasound include: an open skull, an open abdomen and severe limb abnormalities. These abnormalities are rare!

Centres and specialist areas

Pregnancy and birth

Latest publication date: 22/02/2021