Clinical and laboratory study of children exposed in utero to maternal rubella.

Clinical and serological findings are described in 218 children aged 1 to 4 years who were exposed in utero to maternal rubella infection, and who were apparently normal at birth. 84 children were reassessed at 6 to 8 years of age. At the first examination, 23% of children had rubella-like defects, the most common of which was deafness associated in some cases with retinopathy. There was a close correlation between the incidence of rubella defects and both the time of exposure to maternal rubella and the presence or absence of rubella antibodies in the blood at the first examination (1 to 4 years). Children who were seropositive and who were exposed to maternal rubella before the 20th week of pregnancy were at highest risk. Of the 84 children who were reassessed at 6 to 8 years of age, further defects were detected in 9 out of the 49 seropositive children. No further defects were encountered in the seronegative group. 17% of initially seropositive children showed loss of antibody by the second examination, but this, with one exception, was confined to normal children with low antibody titres. These findings stress the importance of long-term follow-up in children at greatest risk.