Trends in maternal age distribution and the live birth prevalence of Downs syndrome in England and Wales: 19382010This article has been corrected since online publication and a corrigendum is also printed in this issue

There have been concerns about the effects of increases in maternal age since the 1980s on the prevalence of Down’s syndrome. This study examined changes in the distribution of maternal age in England and Wales from 1938 to 2010. The live birth prevalence of Down’s syndrome in the absence of screening and subsequent termination was estimated using the numbers of babies born in England and Wales according to maternal age and the maternal age-related risk of a birth with Down’s syndrome. The proportion of women age 35 years or older at the time of giving birth reached a peak of 20% in 1945, declined to 5.5% in 1977 and rose to 20% in 2007. In the absence of screening and subsequent termination, the estimated live birth prevalence of Down’s syndrome would have mirrored these changes (2.3 per 1000 births in 1945, 1.2 per 1000 in 1976 and 2.2 per 1000 in 2007). The observed live birth prevalence (recorded by the National Down Syndrome Cytogenetic Register) was1.0 per 1000 from 1989 to 2010, due to screening and subsequent termination. In conclusion since the 1980s there has been an increase in the mean maternal age and in the expected prevalence of Down’s syndrome. When put in a longer historical context the current expected live birth prevalence is similar to that in the 1940s and the observed live birth prevalence is about 54% less than expected, due to screening and subsequent termination, and has remained reasonably constant since 1989 at 1.0 per 1000 births. European Journal of Human Genetics (2013) 21, 943–947; doi:10.1038/ejhg.2012.288; published online 30 January 2013

[1]  Lyubov Yevtushok,et al.  Twenty-year trends in the prevalence of Down syndrome and other trisomies in Europe: impact of maternal age and prenatal screening , 2012, European Journal of Human Genetics.

[2]  C. Cantor,et al.  Noninvasive detection of fetal trisomy 21 by sequencing of DNA in maternal blood: a study in a clinical setting. , 2011, American journal of obstetrics and gynecology.

[3]  Yama W. L. Zheng,et al.  Non-invasive prenatal assessment of trisomy 21 by multiplexed maternal plasma DNA sequencing: large scale validity study , 2011, BMJ : British Medical Journal.

[4]  X. Bian,et al.  Current situation and development of prenatal diagnosis in China , 2010, Frontiers of medicine in China.

[5]  Lilah M. Besser,et al.  Prevalence of Down Syndrome Among Children and Adolescents in 10 Regions of the United States , 2009, Pediatrics.

[6]  E. Alberman,et al.  Trends in Down’s syndrome live births and antenatal diagnoses in England and Wales from 1989 to 2008: analysis of data from the National Down Syndrome Cytogenetic Register , 2009, BMJ : British Medical Journal.

[7]  John Burn,et al.  Twenty-year trends in prevalence and survival of Down syndrome , 2008, European Journal of Human Genetics.

[8]  G. Savva,et al.  Ascertainment and accuracy of Down syndrome cases reported in congenital anomaly registers in England and Wales , 2008, Archives of Disease in Childhood Fetal and Neonatal Edition.

[9]  M Vrijheid,et al.  Congenital anomaly surveillance in England—ascertainment deficiencies in the national system , 2004, BMJ : British Medical Journal.

[10]  D E Mutton,et al.  Revised estimates of the maternal age specific live birth prevalence of Down's syndrome , 2002, Journal of medical screening.

[11]  G. Yeo,et al.  Birth prevalence of Down syndrome in Singapore from 1993 to 1998. , 2002, Singapore medical journal.

[12]  D. Mutton,et al.  Results of first year (1989) of a national register of Down's syndrome in England and Wales. , 1991, BMJ.

[13]  H. Cuckle,et al.  Estimating a woman's risk of having a pregnancy associated with Down's syndrome using her age and serum alpha‐fetoprotein level , 1987, British journal of obstetrics and gynaecology.

[14]  Joan K. Morris,et al.  The National Down Syndrome Cytogenetic Register for England and Wales: 2009 Annual Report , 2010 .

[15]  E. Muggli,et al.  Is Down syndrome a disappearing birth defect? , 2008, The Journal of pediatrics.