Abstract
At present 40% of congenital deafness is inexplicable. The effect of rubella on the frequency of congenital deafness was studied 5 years after an epidemic of rubella in an island population. Of 87 congenitally deaf children born in 1961, the year after the epidemic, 86 had deafness as the only demonstrable congenital abnormality. Only 20 gave a history of first-trimester rubella. By modern classification the remaining 67 cases should be labeled as idiopathic congenital deafness, all known causes for congenital deafness having been ruled out. Serologic tests for rubella antibodies on 30 of the idiopathic deaf children were positive in 74%, as compared to 30% in a control group born within the same year. This study suggests asymptomatic rubella infection in the first trimester as an etiologic factor in congenital deafness.