A major new study from the University of Aberdeen has revealed the most comprehensive national picture to date of the number of babies with Down’s syndrome in Scotland.
The findings offer crucial insights for families, clinicians and policymakers as pregnancy screening for Down’s syndrome continues to evolve.
The research, published in The Lancet Regional Health – Europe, was conducted as part of a Medical Research Scotland-funded PhD in partnership with Public Health Scotland.
Researchers from the University of Aberdeen and Public Health Scotland analysed national data covering around 1.2 million births across Scotland between 2000 and 2021 and found that Down’s syndrome remains relatively rare, with 2,098 babies diagnosed over the 21-year period. This equates to around 17 babies per 10,000 total births and around nine live born babies per 10,000 live births.
Led by Dr Rute Vieira from the University of Aberdeen, the study examined whether the chance of having a baby with Down’s syndrome differed according to maternal age, NHS health board of residence or area-level deprivation.
All babies diagnosed with Down’s syndrome were included in the study, whether the pregnancy ended in a live birth or a pregnancy loss (miscarriage, termination of pregnancy or stillbirth).
The number of live born babies with Down’s syndrome remained consistent over the full 21‑year period, but the total number of babies with Down’s syndrome (live born babies and those where the pregnancy ended in a loss) did change. The study shows that the total number of babies with Down’s syndrome remained broadly stable between 2000 and 2012, increased between 2013 and 2015, and then declined from 2016 onwards.
Researchers say the pattern may reflect improvements in pregnancy screening and detection and differences in how health records have been captured over time.
Maternal age continues to be strongly linked to the chance of having a baby with Down’s syndrome. The study found that the likelihood of having a baby with Down’s syndrome increased sharply for women aged 35 and over: women aged 35 to 39 had around 5.4 times the chance compared with women under 25.
Where mothers live also appeared to make a difference. The team observed significant differences between some NHS health boards and between deprivation groups, indicating geographic and socioeconomic variation within Scotland. The researchers say further work should be carried out to investigate why this may be. This variation may at least partially reflect differences in how health records have been captured over time and associated data quality.
The findings provide an important benchmark for understanding the impact of non‑invasive prenatal testing (NIPT), introduced in Scotland in 2020 as a safe and more accurate follow-up screening test for women who receive a higher‑chance result for Down’s syndrome from initial pregnancy screening. With the roll‑out of NIPT still relatively recent, these long‑term figures will help researchers monitor how screening uptake, timing of diagnosis and pregnancy outcomes may change in the coming years.
Researchers say the work will support more accurate counselling for expectant parents and help Scotland plan services for children with Down’s syndrome, who are more likely to require additional healthcare support in early life.
Dr Rute Vieira said: “By analysing more than two decades of national data, this study provides the clearest picture so far of how Down’s syndrome prevalence has changed in Scotland. While the number of babies born with Down’s syndrome has remained stable, our findings show how strongly maternal age is associated with the likelihood of a diagnosis during pregnancy.
“These results are important for ensuring that expectant parents are given accurate, up-to-date information when making decisions about screening and diagnostic testing. They also provide essential evidence for healthcare planning and will help researchers and policymakers monitor how changes to prenatal screening, including the introduction of non-invasive prenatal testing (NIPT), may influence diagnoses and pregnancy outcomes in the future.”
Dr Rachael Wood from Public Health Scotland said: “Public Health Scotland has been working to improve national data on babies with congenital conditions such as Down’s syndrome, and on the national pregnancy and newborn screening programmes including pregnancy screening for Down’s syndrome and other chromosomal conditions. It is important that these data are used to understand trends in these conditions and the performance and impact of the national screening programmes, and ultimately to improve health outcomes for babies and families across Scotland.”
Jo Hughes, Head of Service Development, Down’s Syndrome Scotland said: “This important and encouraging research provides clear long‑term insights that support informed decisions around future policymaking and healthcare planning, while giving parents more up‑to‑date information about screening and what to expect; we hope the findings also help make pregnancy screening more consistent across Scotland and ensure families who have a baby with Down’s syndrome receive the right support from pregnancy and throughout life”.
Professor Matthew Walters, Chair of Medical Research Scotland, said: “Medical Research Scotland is proud to have supported this important study, which provides valuable evidence to inform policy, practice and support for families. This research reflects our commitment to backing high-quality work with real-world impact, improving lives in Scotland and beyond.”