Cytomegalovirus (CMV) transmission from mother to fetus occurs at a much greater rate following primary rather than reactivated infections and CMV dissemination in the mother is considered a key step in the pathogenesis of fetal infection. However, knowledge of CMV DNAemia in CMV-seropositive pregnant women is very limited.Major objective of this study was to assess the prevalence and diagnostic value of CMV DNAemia in a large population of seropositive pregnant women.Serologic and DNAemia results obtained from 2211 blood samples of 1371 consecutive pregnant women referred to our Institution for suspected CMV infection in the period 2001-2010 were reviewed.DNAemia was detected in 452/597 (75.7%) women with serologic evidence of primary CMV infection and in 4/774 (0.5%) women without evidence of primary infection.In pregnant women, CMV DNAemia is detected primarily during primary infection. CMV DNAemia determination may be helpful in the diagnosis of primary infection.