[Impact of maternal age distribution on the expected live birth prevalence of Down's syndrome in the metropolitan France between 1965 and 2008]

Abstract

Objectives: To evaluate the impact of demographic factors such as maternal age on the expected prevalence of Down's syndrome at birth.

Patients and methods: We used data from the French National Institute of Statistics (INSEE) concerning live births and maternal age. Expected prevalence at birth is derived from a mathematical regression model commonly used in biochemical screening.

Results: We present continuous expected prevalence at birth over a long period, from 1965 to 2008. Over the last three decades, mean maternal age has increased by 4 years, leading to a two-fold increased in the expected live-birth prevalence of Down's syndrome infants, from 12.1 per 10,000 in 1977 to 21.7 per 10,000 in 2008.

Conclusion: It is important to continue to consider the impact modifications in demographic factors, such as maternal age, particularly in the evaluation of screening practices and policies for Down's syndrome.