Maternal IgM antibody status in confirmed fetal cytomegalovirus infection detected by sonographic signs.

OBJECTIVE: To evaluate the value of maternal IgM to cytomegalovirus (CMV) as a predictive factor of fetal infection in fetuses with sonographic markers. METHODS: Observational study (2006-2011) including a consecutive series of 19 fetuses with sonographic markers of fetal infection and confirmed infection by positive CMV-DNA in amniotic fluid or fetal blood. We evaluated the status of maternal CMV IgM at the time of sonographic suspicion. RESULTS: During this 6-year study period, CMV infection was diagnosed in 19 fetuses from 18 pregnancies, including 16 singletons, both twins of a monochorionic diamniotic pregnancy and one twin of a dichorionic pregnancy. Sonographic suspicion was established on the basis of one or more of the following: brain abnormalities (14), fetal hydrops (4), hyperechogenic bowel (4), pericardial effusion (1), cardiomegaly (1), oligoanhydramnios (4), and placentomegaly (2). Maternal IgG antibodies were positive in all cases but maternal IgM antibodies were negative in 56% of pregnancies. Five of the 10 pregnancies with negative maternal IgM were diagnosed in the second trimester and five in the third trimester. CONCLUSION: In around half of fetuses with confirmed CMV infection ascertained by sonographic markers, maternal IgM antibodies are negative and should therefore not be used as a diagnostic parameter.