In 2004 The Danish National Board of Health introduced a new guideline regarding prenatal screening. All pregnant women are now offered a Down's syndrome risk assessment. The new guideline has had an impact on the number of invasive early prenatal procedures. The number of procedures fell by 50% from 2000 to 2006. 90% of the foetuses with Down's syndrome are detected prenatally. Denmark is one of the first countries in the world in which risk assessment for Down's syndrome has been successfully implemented at a national level.