[Variations in the prevalence of Down's syndrome in the French population between 1978 and 2005]

To evaluate the impact of maternal age and prenatal diagnosis on the prevalence of Down's syndrome at birth in French population sample.

Data concerning Down's syndrome from 1978 to 2005 were obtained from the REMERA registry of congenital malformations. The population surveyed was approximately 10% of French births. We studied total prevalence, live-birth prevalence and the prevalence of pregnancy termination after prenatal diagnosis.

Mean maternal age has risen from 26 to 30 years over the study period. Total prevalence of Down's syndrome has increased from 14 per 10,000 in 1978 to 23 per 10,000 live-births in 2005. Termination of pregnancy after prenatal diagnosis of Down's syndrome gradually increased reaching 78% in 2005. Live-birth prevalence decreased from 14 per 10,000 in 1978 to 5.1 per 10,000 in 2005.

This work shows the importance of continuing the epidemiological survey of Down's syndrome in France, especially because of the modification in population ageing as well in prenatal screening policies for Down's syndrome.