Nuchal translucency scan
Nuchal translucency (NT) is the Sonographic appearance of a collection of fluid under the skin behind the fetal neck in the first-trimester of pregnancy. The term translucency is used, irrespective of whether it is spotted or not and whether it is confined to the neck or envelopes the whole fetus. In fetuses with chromosomal abnormalities, cardiac defects and many genetic syndromes the NT thickness is increased.
Normal nuchal translucency
Early screening for chromosomal abnormalities
The Fetal Medicine Foundation (FMF) has introduced a process of comprehensive training, support and audit of the proper implementation of early screening for chromosomal abnormalities. The FMF advocates that effective screening requires:
- Carrying out the ultrasound examination by appropriately trained Sonographers.
- Measurement of maternal serum free β-hCG and PAPP-A by laboratories that can demonstrate good quality assurance performance.
- A risk calculation program that uses an algorithm based on scientific evidence. The software companies that use this algorithm are Astraia Software GmbH, ViewPoint GE Healthcare and Zeitgeist Health SE.
- Appropriate counseling of the parents.
Sonographers who have obtained the FMF Certificate in the Nuchal translucency (NT) scan can obtain free of charge the FMF software for first-trimester screening for chromosomal abnormalities by maternal age, fetal NT thickness and maternal serum free β-hCG and PAPP-A. Should they wish to use the additional markers for chromosomal abnormalities (nasal bone, Tricuspid flow and Ductus Venosus flow) they would need to obtain the appropriate FMF Certificate for each of these markers.