Prenatal diagnosis of fetal cytomegalovirus infection in seropositive pregnant women.

Thirty two pregnant women, immune to human cytomegalovirus (HCMV) before conception, were examined with a combination of amniocentesis, and blood sampling for fetal HCMV infection. The pregnant women had no history of recurrent infection and they all had normal ultrasonographic findings. Maternal sera and amniotic fluids were examined for anti-HCMV antibodies and viral DNA by enzyme immunoassay and polymerase chain reaction (PCR). All maternal sera were negative for viral DNA and IgM anti-HCMV antibodies. However, HCMV DNA was detected in the amniotic fluid of four pregnant women. These four cases were considered as fetal HCMV infections. Three of them were followed up after birth. The three neonates appeared clinically normal at birth, but HCMV DNA was detected in their urine specimens and in two of them in the cord blood sera. Although the neonates were asymptomatic at birth, the possibility of developing sequelae later on, cannot be excluded. The results show that HCMV recurrent maternal infection is silent and difficult to be suspected and diagnosed. They also show that fetal HCMV infection is not rare among pre-immune pregnant women.