Potential outcomes of maternal CMV infection during pregnancy

CMV: cytomegalovirus; IgM: immunoglobulin M; IgG: immunoglobulin G.
* Primary maternal CMV infection is defined as initial acquisition of virus during pregnancy. Seroconversion from negative to positive is diagnostic, if available. Primary infection is strongly suspected if IgM and IgG are positive and IgG has low avidity.
¶ Nonprimary maternal CMV infection refers to women whose initial acquisition of CMV occurred before pregnancy. It is characterized by presence of maternal anti-CMV antibodies before conception. Like other herpes viruses, CMV establishes latency after the host is initially infected. Women with nonprimary infection may have reactivation of latent virus or reinfection with a new strain during pregnancy.
Δ 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. In one review, there were no symptomatic newborns among 92 pregnancies with third-trimester maternal infection. In another study, there were no symptomatic newborns among women who seroconverted in the periconception period.