Investigation of a cluster of children with Down's syndrome born to mothers who had attended a school in Dundalk, Ireland

Table 6

Maternal age specific incidences of Down's syndrome (per 10⁴ live births) for various areas of Ireland (numbers of live births with Down's syndrome are given in parentheses)

6-150 The number of Down's syndrome live births in each maternal age group is not given by O'Brien and Crowley,16 but overall there were 225 Down's syndrome babies among 111 208 live births.
6-151 Includes 956 live births and (with appropriate adjustment, see text) 74 cases of positive prenatal testing and subsequent induced abortion.