Prenatal diagnosis of fetal primary cytomegalovirus infection

Objective: To determine the reliability of prenatal diagnosis for congenital cytomegalovirus in women with primary infection. Design: Retrospective analysis of case records between 1992 and 1997. Setting: Fetal medicine unit of a large teaching hospital. Population Forty-two pregnant women with primary cytomegalovirus infection. Methods: Fetal diagnosis was made by amniocentesis for viral culture and amplification of cytomegalovirus DNA by polymerase chain reaction (n = 37), or by cordocentesis for the detection of cytomegalovirus -specific IgM antibodies (n = 13). All patients had serial ultrasonographic scans in order to detect those fetuses with abnormalities that could be associated with cytomegalovirus infection. Results: Fourteen pregnancies (33.3%) had evidence of vertical transmission. Nine out of 14 (64.3%) had positive amniotic fluid culture, while 11 (78.6%) had positive polymerase chain reaction results. The combination of both tests allowed antenatal diagnosis in 12 of the 14 infected fetuses (sensitivity 85.7%). All women who underwent cordocentesis for the detection of cytomegalovirus-specific IgM antibodies had negative results, but in two cases cytomegalovirus infection was detected by amniotic fluid studies. In five of the infected fetuses there were abnormal ultrasonographic findings. All pregnancies with evidence of vertical transmission were terminated and the remainder proceeded normally to term. Conclusions: Our data showed that amniotic fluid studies, preferably polymerase chain reaction amplification of viral DNA, are the best diagnostic tools for the detection of vertical transmission in pregnancies with primary cytomegalovirus infection. For women with positive amniotic fluid studies who elect to continue their pregnancies, cordocentesis and serial ultrasound scans may be useful for assessment of fetal status.