Leeds Fetal Medicine Unit Website

Early pregnancy scans and nuchal scans

Early pregnancy scans are performed in the Leeds fetal medicine unit from 6 weeks of pregnancy usually through abdominal scanning, but occasionally using a vaginal probe, at this stage the presence or absence of the fetal heart can determine whether a pregnancy is viable. The number of fetuses present and their gestation (within 5 days) can accurately be determined from 8 weeks. After 11 weeks anatomical features can be examined though only in limited detail, these include the developing fetal brain, the fetal heart, the fetal stomach, the fetal bladder and the fetal limbs.

Nuchal translucency scans

Nuchal transluceny scans are performed in the Leeds fetal medicine unit by doctors and ultrasonographers accredited by the Fetal Medicine Foundation. The nuchal translucency scan is performed between when the fetal crown rump length (head to bottom length) is between 45 and 80mm (this equates to approximately 11 to 13 weeks of pregnancy) and measures a thickness at the back of the fetal neck. A thickened nuchal translucency is associated with

Chromosomal abnormalities (e.g. Down's syndrome, see Genetic information for patients)
Cardiac abnormalities
Genetic syndromes
Structural problems

Once a nuchal translucency has been obtained the risk of chromosomal abnormalities is calculated using a computer programme (which we are licenced to use by the Fetal Medicine Foundation). Other associations with thickened nuchal translucencies (such as cardiac abnormalities) can often not be detected until later in pregnancy.

Patient Information leaflet please click here

Information for medical professionals on the overall outcomes of fetuses with thickened NTs is available here

Currently we do not perform nuchal translucency scans for low risk pregnant women (these are available privately in Yorkshire at the Leeds Screening Centre and Yorkshire Obstetric Ultrasound Services). We do perform nuchal translucency scans for specific high risk pregnancies (usually following a previous abnormal pregnancy) or for multiple pregnancies where triple testing is not reliable.

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