maternal age and chance of Down's syndrome
Last edited 05/2023 and last reviewed 05/2023
The chance of having a baby with Down's syndrome is related to the age of the mother, approximately as follows:-
The levels of chance associated with having a Down's syndrome pregnancy in relation to a woman's age are shown in the table below:
Woman's age (years)
|Chance as a ratio||%Chance|
|45 and over||1.50 and greater||2.0|
If the mother of an affected child is under 36 then the chance of a further child being affected is said to be about 1 in 100.
Note however that the absolute numbers of mothers having children with Down's syndrome is greater in the younger age groups; this is because the total number of mothers in these groups is much higher.
For more information then see https://view-health-screening-recommendations.service.gov.uk/downs-syndrome/