Changes in yearly birth prevalence rates of children with Down syndrome in the period 1986-2007 in The Netherlands.
Despite wider prenatal screening, Dutch Down syndrome births have risen since the 1990s, so BCBAs should ready services for a growing lifespan.
01Research in Context
What this study did
de Graaf et al. (2011) counted every baby born with Down syndrome in the Netherlands. They looked at 22 years of hospital records, from 1986 to 2007.
The team wanted to see if better prenatal tests were lowering the number of Down syndrome births.
What they found
Births went up, not down. About 11 babies per 10,000 had Down syndrome in the early 1990s. By 2007 it was about 14 per 10,000.
Older moms explain the rise. More women now have babies after age 35, when Down syndrome risk is higher.
How this fits with other research
Takenoshita et al. (2026) followed Japanese adults with Down syndrome and found one in three had dementia. Together the papers show the same group tracked from birth to older age.
Sánchez Moreno et al. (2024) show what kills Spanish adults with Down syndrome: mostly lung infections. Their data fit the Dutch rise—more births mean more adults needing lung care later.
Howlin et al. (2006) give a warning sign: middle-aged adults who interrupt word lists often slide into memory loss soon after. The growing Dutch birth cohort will need this quick screen.
Why it matters
You will meet more clients with Down syndrome, not fewer. Plan now for longer waits, bigger caseloads, and adult services. Track verbal intrusions and blood pressure early. Push for COVID and flu shots, because lung illness is the top killer in adulthood.
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02At a glance
03Original abstract
BACKGROUND: The Netherlands are lacking reliable national empirical data in relation to the development of birth prevalence of Down syndrome. Our study aims at assessing valid national live birth prevalence rates for the period 1986-2007. METHOD: On the basis of the annual child/adult ratio of Down syndrome diagnoses in five out of the eight Dutch cytogenetic centres, the national annual figures of the National Cytogenetic Network on total numbers of postnatal Down syndrome diagnoses were transformed into national figures on total numbers of postnatal Down syndrome diagnoses in newborn children only. In combination with the national annual data of the Working Group for Prenatal Diagnostics and Therapeutics on numbers of Down syndrome pregnancies not aborted after diagnosis, national figures on birth prevalence were constructed. RESULTS: For the period 1986-2007, results based on the data of the cytogenetic centres are almost similar to the theory-based model data of de Graaf et al., with a small discrepancy of approximately 4%. Down syndrome birth prevalence in the Netherlands shows an upward trend from around 11 per 10,000 births in the early 1990s to around 14 per 10,000 births nowadays. CONCLUSION: In spite of expansion of antenatal screening in the Netherlands, Down syndrome live birth prevalence has risen in the last two decades as a result of rising maternal age. This increase in Down syndrome birth prevalence is in contrast to studies from other European countries.
Journal of intellectual disability research : JIDR, 2011 · doi:10.1111/j.1365-2788.2011.01398.x