Sources had different reporting patterns

EDITOR—Stone et al have a very different view from ours of abdominal wall defects in our regions (former South East Thames and North West Thames).1 As they acknowledge, the cited rates for abdominal wall defects were derived from sources with different reporting patterns. In particular, the rates quoted for England and Wales were from data from the Office for National Statistics,2 which take no account of terminations for abnormalities diagnosed prenatally, whereas the Glasgow and northern England registers have tried to be comprehensive.

More appropriate north-south comparisons could have been achieved from the rates reported by individual regional registers such as those in the former South East Thames and North West Thames regions. These registers obtain data in a similar manner to the northern regional registers, with active data collection from …