Congenital Cytomegalovirus Infection: The Relative Importance of Primary and Recurrent Maternal Infection

We studied the incidence of primary and recurrent cytomegalovirus infection in 3712 pregnant women —2698 of middle to high income and 1014 of low income — to determine whether there were differences in the effects on the fetus. In the higher-income group, 1203 women (45 per cent) did not have antibodies to cytomegalovirus and were therefore susceptible to primary infection, as compared with 179 women (18 per cent) of low income. Congenital infection occurred more often (1.6 vs. 0.6 per cent) in infants in the low-income group. In this group it was associated with recurrent maternal infection more often (in 82 per cent) than with primary maternal infection, whereas in the upper-income group, it was associated with primary maternal infection in half the cases. Altogether, there were 32 cases of congenital cytomegalovirus infection — 16 in each group. Whereas primary maternal infection resulted in fetal infection in only half the cases, it was more likely to be associated with clinically apparent disease than was recurrent infection. When these cases were combined with 28 cases of congenital infection retrospectively identified at other prenatal clinics, five of 33 infected infants born after primary maternal infection had clinically apparent disease, as compared with none of 27 born after recurrent maternal infection. We conclude that congenital cytomegalovirus infection resulting from primary maternal infection is more likely to be serious than that resulting from recurrent infection, and is more likely to occur in upper socioeconomic groups. (N Engl J Med. 1982; 306:945–9.) CYTOMEGALOVIRUS is the leading cause of congenital viral infection, with an average incidence of 1 per cent of all live births. 1 Clinically, this infection is largely inapparent in the neonatal period. It is estimated that only 5 to 10 per cent of those infected have the more virulent form (whose signs and symptoms range from fatal illness to moderate hepatosplenomegaly, jaundice, and petechiae), and late complications develop almost invariably among survivors in this group. 2 3 4 5 6 Another 10 per cent of infants with subclinical congenital infection will subsequently have varying degrees of perceptual, neurologic, psychomotor, or behavioral complications during the preschool years. . . .