Consequences of Natural Exposure to Rubella during Pregnancy ∗

Abstract

Summary

Blood specimens collected early in pregnancy and again at delivery from 347 women with histories of exposure to rubella were tested for antibodies by the indirect fluorescent-antibody technique. Gamma globulin had been administered to 72 following exposure. Previous immunity was detected in 265 of the women who were found to have antibodies of identical titer in both specimens. Serological evidence of infection during pregnancy was demonstrated in 41 of the 82 women whose first sera were negative for antibodies. Twenty-six of these infections were subclinical and only 15 were recognized as clinical rubella. Gamma globulin did not reduce the incidence of infection in susceptible women, which was actually higher than in the uninjected, but markedly suppressed the development of clinical disease. Damage to the fetus following first trimester infection resulted only once among 14 pregnancies in which gamma globulin had been administered. By contrast, four of 27 pregnancies of un-inoculated women terminated abnormally, even though 20 of them were infected after the first trimester. There was evidence of delayed infection following injection of gamma globulin and the possible significance of this phenomenon is discussed.