Introducing a non-invasive prenatal test to Wales

The All Wales Medical Genomics Service received the Efficiency through Technology - High Impact Award at the MediWales Innovation Awards for developing a non-invasive prenatal test to screen for Down’s syndrome and other conditions.

In 2018, Wales became the first UK nation to offer non-invasive prenatal testing (NIPT) as part of the Antenatal Screening Programme. This type of test is designed to substantially reduce the number of pregnant women being offered invasive tests and therefore reduce the associated risk of miscarriage. The NIPT service is now entering its third year and remains the only UK NHS commissioned service.

Implementing a new genomic technique in a pre-existing NHS setting is a complex multilevel process. The All Wales Genetics Laboratory developed an in-house NIPT test by means of a ‘technical transfer’ option available from an external company (Illumina).

Before 2018, screening for Down’s syndrome in Wales was based on a combined screening test. This test has a false positive rate of around 5 per cent, which translates to over 10 invasive procedures carried out for each Down’s syndrome diagnosis. Reducing the number of invasive procedures performed (testing by amniocentesis or by chorionic villus sampling) was desirable, since invasive tests carry an increased risk of fetal loss (around 1%) and are also expensive procedures for the NHS. NIPT made its first commercial debut in the United States in 2011, and pregnant women have increasingly gained access to this test within the UK through private provision, leading to inequality of access.

During the first year of NIPT implementation (April 2018 – March 2019) within NHS Wales, the genetics laboratory processed 552 samples from women found to be at a higher chance of Down’s syndrome, Edwards syndrome and Patau syndrome from the initial screening offer. 90 per cent of pregnant women received a low chance NIPT report for these conditions, meaning that for these women further invasive testing did not need to be offered. Data has shown a significant annual reduction in invasive samples received by the laboratory since the introduction of NIPT, meaning that significantly fewer women have had to place their pregnancy at risk.

Incorporating NIPT into NHS Wales has improved overall public health, because fewer invasive prenatal procedures means lower miscarriage rates for women. It has also improved patient care, since patients now have access to the most effective antenatal screening test available on the NHS and it is an equitable service for all pregnant women across Wales.