NCARDRS Congenital Anomaly Official Statistics Report, 2021

Trisomy is a condition that results in an extra copy of a chromosome in all or some of an individual’s cells. Down’s syndrome (Trisomy 21), Edwards’ syndrome (Trisomy 18) and Patau’s syndrome (Trisomy 13) are the most common forms of trisomy associated with pregnancies that can progress to full term. To ensure consistency throughout the report and internationally, partial trisomies are also included in the trisomy groups for prevalence reporting.

Figure 3 (Data table 1) shows the prevalence of Down’s syndrome in 2021 was 29.7 (95% CI 28.4-31.1) per 10,000 total births or one in every 336 births, prevalence of Edwards’ syndrome was 9.2 (95% CI 8.5-10.0) per 10,000 total births or one in every 1,086 births and prevalence of Patau’s syndrome was 3.3 (95% CI 2.8-3.8) per 10,000 total births or one in every 3,048 births.

Live birth prevalence in 2021 was 11.7 (95% CI 10.9-12.6) per 10,000 live births or one in 854 live births for Down’s syndrome, 0.7 (95% CI 0.5-1.0) per 10,000 live births or one in 13,591 for Edwards’ syndrome and 0.4 (95% CI 0.3-0.6) per 10,000 live births, or one in 23,001 for Patau’s syndrome respectively. This was relatively consistent with previous years for Down’s syndrome and Edwards’ syndrome but higher for Patau’s syndrome relative to 2020 when it was 0.2 (95% CI 0.1-0.4).

Figure 3: Prevalence of Down’s syndrome, Edwards’ syndrome and Patau’s syndrome per 10,000 total births and per 10,000 live births in England and the Crown Dependencies, 2021