IgM antibodies to cytomegalovirus during pregnancy.

IgM antibodies to cytomegalovirus (CMV) could be detected in about 7 per cent of 629 pregnant women whereas in 225 nonpregnant control women of similar age distribution only 2.6 per cent showed CMV IgM antibodies. Intrauterine CMV infections were almost exclusively detected among the CMV IgM positive gravides. The high incidence of CMV IgM antibodies in pregnant women can be possibly explained by an increased rate of CMV reactivations during pregnancy. We were able to show that during CMV reactivation an intrauterine infection might occur.