Seasonal variation in anencephalus in Canada

Abstract

A study of the monthly numbers of stillbirths and of deaths due to anencephalus in Canada from 1954 to 1962 showed a weak tendency to a winter excess of affected births. The seasonal trend was more marked in the Prairie provinces and in Quebec than elsewhere; the maximum rate of anencephalus occurrence was from October to December in the Prairies and in British Columbia, and from January to March in other regions.