The medical significance of date of birth

Abstract

There is clear evidence of month-to-month variation in infant mortality and in the occurrence of several congenital malformations including anencephaly, patent ductus arteriosus, and congenital dislocation of the hip. In addition, there is suggestive evidence for seasonal cycles in births of persons with several other conditions arising during fetal life or early infancy. The data do not suggest that further examination of birth-date cycles in relation to diseases appearing in older children or adults holds much promise. Much more work is needed on the observed association between date of birth and congenital malformations, particularly with respect to sex ratio and to seasonal variations in specific noxious stimuli which might injure developing fetuses, such as maternal infections or ingestion of various foods and drugs. A large amount of effort has been expended on the study of date of birth and various conditions of medical interest, but relatively few such correlations have been found and adequately confirmed.