Mussi-Pinhata MM, et al. - Seronegative pregnant women living in a high seroprevalence population were analyzed for the risk of seroconversion. Researchers determined CMV-IgG reactivity at the 1st trimester in all women and sequentially for seronegative women. They identified 1915/1952 women as seropositive, and 36 as seronegative. Seroconversion was observed in 5/36-seronegative women. Most CMV-infected infants were born to women with preexisting seroimmunity even with a high risk of primary infection in seronegative women.