Incidence of chromosome abnormalities in newborn children. Comparison between incidences in 1969-1974 and 1980-1982 in the same area.

As part of an ongoing study of the influence of environmental factors on pregnancy, childbirth, and fetuses, comparisons have been made between incidences in 1969-1974 and in 1980-1982 of chromosome aberrations in liveborn children in the same area of Denmark. The incidence of chromosome aberrations in the first period was 2.6 per 1000, compared with 41. per 1000 during the latter period. However, the difference was mainly due to an increase in inversions, and this in turn was due to a difference in chromosome staining methods between the two periods. It is concluded that the Danish study and similar studies in the United States, Canada, and Scotland indicate that early detection of chromosome aberrations by chromosome examination at birth is indicated in order to be able to inform and counsel parents of children with chromosome aberrations. Chromosome examination at birth is also of importance in the diagnosis of structural inheritable chromosome aberrations and consequent family investigation and genetic counseling.