Down Syndrome : Screening Guide for Primary Care Clinicians

In the UK, the screening for Down Syndrome is a vital part of prenatal care, offering expectant parents valuable information about the likelihood of their baby being born with this genetic condition. Down Syndrome, also known as Trisomy 21, is characterized by the presence of an extra copy of chromosome 21 and is associated with a variety of physical and developmental traits.

The screening process in the UK is designed to be non-invasive and risk-free for both the mother and the baby. It typically involves a series of tests conducted at different stages of pregnancy to assess the risk of the baby having Down Syndrome, Edwards’ syndrome (Trisomy 18), or Patau’s syndrome (Trisomy 13). Parents are given the choice to opt for this screening and can decide the extent of conditions they want to screen for.

The UK National Screening Committee (UK NSC) advises a two-tiered approach for Down syndrome (Trisomy 21) screening during pregnancy:

1. Combined Test (10-14 weeks):

   • This screening combines an ultrasound scan for nuchal translucency (fluid at the back of the baby's neck) with blood tests measuring pregnancy hormones (PAPP-A and hCG).
   • It estimates the risk of Down syndrome based on these measurements and the maternal...