Seasonal incidence of anencephalus.

According to the most recent figures, anencephalus has become the second most common cause of stillbirth in England and Wales and the commonest in Scotland. The most revealing data are those published by the Registrar-General for Scotland, where causes of stillbirth have been registered since 1939 (22 years longer than in England and Wales). Between 1939 and 1963 they show a halving of the overall stillbirth rate and a slight increase in the incidence of stillbirths caused by anencephalus. The proportion of all stillbirths attributed to anence- phalus rose from 5-8 per cent. in 193941 to 14-8 per cent. in 1961-63. It follows that, in the effort to reduce prenatal mortality further, studies of the aetiology of anencephalus have an increasingly significant part to play.