Congenital malformations in babies of diabetic mothers.

In 1979-80 a national survey of the incidence of congenital malformations in babies born to diabetic mothers in the United Kingdom was carried out by questionnaire. Of the 1034 mothers reported, 773 were known to have diabetes before the index pregnancy. The incidence of congenital malformations ws 7.1% which is significantly higher than the 2.1% in the offspring reported to the Office of Population, Censuses and Surveys (OPCS) for England and Wales in 1979-80. The increase was most pronounced for malformations of the heart, spine, lungs, and brain. In 40% of the diabetic mothers blood glucose was not recorded during the first trimester of pregnancy, and in this group the malformation rate was twice that in babies born of mothers who had had at least one reported blood glucose estimation during this time. We conclude that there is an urgent need to improve health education and supervision before and during pregnancy in all diabetic women if the prevalence of malformations amongst their offspring is to be reduced.