Diagnostic approach for suspected fetal CMV infection

CMV: cytomegalovirus; PCR: polymerase chain reaction.
* Refer to UpToDate content on CMV infection in pregnancy for a description of the fetal sonographic findings potentially associated with congenital CMV infection. If only a few nonspecific markers of infection are present, it is reasonable to check maternal CMV serology first and then offer amniocentesis if serology is consistent with recent maternal infection.
¶ Most authorities recommend not screening pregnant women for CMV. However, testing for CMV is appropriate in pregnant women with mononucleosis-like illnesses early in pregnancy. Symptomatic disease at birth and severe sequelae occur almost exclusively among offspring of women who seroconvert in the first half of pregnancy, particularly the first trimester. Refer to UpToDate content on CMV infection in pregnancy for a discussion of screening and testing pregnant women for CMV.
Δ Timing of amniocentesis depends on a combination of factors, including gestational age, estimation of when maternal infection occurred, and development of new ultrasound findings suggestive of infection. Sensitivity increases as the interval between maternal infection and amniocentesis increases, but if termination of pregnancy would be considered, then local regulations regarding gestational age limits also factor into this decision.