The authors were interested in the risk of cytomegalovirus (CMV) seroconversion in seronegative pregnant women living in a high seroprevalence population. The authors found that 98% of 1952 women were seropositive in the first trimester of pregnancy and only 1.8% were seronegative. Five of the 36 seronegative women subsequently seroconverted, giving a cumulative rate of 13.9%. Congenital CMV infection was diagnosed in only one of the 36 infants (2.8%) born to seronegative women, compared with eight of 1685 (0.5%) infants born to seropositive mothers. Therefore, even with a high risk of primary infection in seronegative women, most CMV-infected infants were born to women with pre-existing seroimmunity.
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