Mr. Peter Thompson:

It is possible to pick cohorts of women who are statistically more likely to have a baby with a difference, for example, diabetic women or it may be people who have congenital heart disease and who would be significantly more likely to have a baby with that disease than would a woman with a normal heart. In relative terms, however, the majority of foetal abnormalities will still not be detected because the majority of foetal abnormalities will occur in a low-risk population just because there are more low-risk women. That is why the UK screening programme would strongly recommend everybody having a scan at 20 weeks.