An ultrasound scan is performed between 11 and 13 weeks plus 6 days of pregnancy.

• Pre-test counselling is carried out to discuss the test and the meaning of its results. Informed consent is obtained,
  
  
• A careful assessment of the fetal anatomy is carried out (early anomaly study),
  
  
• The NT and the nasal bone are measured,
  
  
• At the end of the exam the Doctor performing the test discusses the result with the patient and her partner.

The sensitivity of the test is increased if biochemical screening is associated with the ultrasound screening. Biochemical screening consists of a test performed on a sample of maternal blood. Two markers are analysed: Free-Beta HCG e PAPP-A. These are “pregnancy related“ markers detectable in the blood of all pregnant women. In the vast majority of pregnancy with an abnormal baby these markers are present in abnormal quantity. The combination of the biochemical and ultrasound screening allows to calculate the risk of Down’s Syndrome, Trisomy 13 and 18.


BIBLIOGRAPHY

Continuous medical education is essential in a area – Prenatal screening - where such rapid changes and developments are taking place.
The following publications and articles are available in PDF Full text:

The 11-13+6 weeks scan (Nicolaides, 2005) (731 Kb)
Contribution of the Author on the assessment of the fetal heart (2007) (Lombardi 2.500 Kb)
Censimento della Società Italiana di Genetica Umana 2003 (462 Kb)
Prenatal diagnosis: CVS and amniocentesis – NHS UK Guidelines 2005 (181 Kb)

(Further information: 758 articles published in the world scientific literature between 2003-2007 have been considered and 220 most relevant articles are quoted (summary).