Studies of the Natural History and Prevention of Rubella

ALTHOUGH RUBELLA is almost invariably a mild, self-limited disease seldom followed by complications or sequelae of any kind, numerous studies have established that at least 15% to 20% of the offspring of women who contract German measles during the first trimester of pregnancy are afflicted with one or more serious and grossly discernible congenital malformations.¹⁻⁸Moreover, if audiometric studies are done, an additional 20% to 30% of such children are found to have some impairment of hearing.⁹The earlier in pregnancy that maternal rubella occurs, the greater is the hazard to the fetus; thus, 50% or more of the children born of women contracting rubella during the first four weeks of pregnancy may have gross congenital