Cytomegalovirus Infection - Podcast Version 0:00 / 0:00 1x 0.25x 0.5x 0.75x 1x 1.25x 1.5x 1.75x 2x Cytomegalovirus is a member of the herpesvirus family (herpesvirus 5). It is the most common virus transmitted to the fetus during pregnancy. Approximately 1 in 100 women become infected with cytomegalovirus during pregnancy (although most remain asymptomatic). Around one third of maternal CMV infections are then vertically transmitted to the fetus. However, only 5% of fetal infections will cause CMV related damage to the fetus, with the risk highest in the first trimester. In this article, we shall look at the clinical features, investigations and management of cytomegalovirus infection during pregnancy. By Emmanuel Boute [CC BY-SA 2.5], via Wikimedia Commons Fig 1Structure of the cytomegalovirus virion. Clinical Features Cytomegalovirus infection is usually asymptomatic in immunocompetent individuals. It can occasionally produce a mild flu-like illness. Alternatively, in some patients, it can cause a mononucleosis syndrome (similar to Epstein-Barr); resulting in fever, splenomegaly and impaired liver function. Investigations If maternal cytomegalovirus infection is suspected, viral serology for CMV specific IgM and IgG is performed. A positive test is signified if: Presence of CMV specific IgG in mother previously seronegative (i.e. seroconversion has occurred). Presence of CMV IgM and low IgG avidity (<30%). Note: Avidity refers to the strength with which the antibody binds to the antigen. Management All women with confirmed cytomegalovirus infection during pregnancy should be referred to a fetal medicine specialist. Maternal In an immunocompetent woman, no treatment of the infection is required. The licensed anti-CMV drugs (ganciclovir, cidofovir and foscarnet) have potential teratogenic effects and a well-known toxicity profile (haematological and renal), and thus are not recommended for use in pregnancy. Fetal Fetal CMV infection can be diagnosed prenatally via amniocentesis and PCR of the resulting amniotic sample. This must be carried out after 21 weeks gestation because functioning fetal kidneys are required for the virus to be excreted into the amniotic fluid. If fetal CMV infection is confirmed, there is no effective therapy, and termination of pregnancy can be offered. If the woman wishes to continue the pregnancy, serial ultrasound scanning should be performed to assess for manifestations of congenital CMV. Promising results have been shown in trials using IV CMV specific hyperimmune globulin. Further research is required before widespread adoption of this as a treatment for fetal CMV infection. Congenital Cytomegalovirus Neonates born following an intrauterine CMV infection can have several problems: Intrauterine growth restriction Hepatosplenomegaly Thrombocytopaenic purpura Jaundice Microencephaly Chorioretinitis There is 20-30% mortality in this symptomatic group. This is often due to disseminated intravascular coagulation (DIC), hepatic dysfunction and/or bacterial superinfection. Babies born without symptoms of CMV infection have a 10-15% chance of developing sequelae of the infection within 2 years. This may include: Sensorineural hearing loss Psychomotor development delay Visual impairment Frequent questions What is cytomegalovirus and how is it transmitted during pregnancy? Cytomegalovirus (CMV) is a member of the herpesvirus family and is the most frequently transmitted virus to the fetus during pregnancy. Approximately 1 in 100 pregnant women become infected, with about one-third of these infections being passed on to the fetus. What are the clinical features of cytomegalovirus infection? Cytomegalovirus infection is typically asymptomatic in healthy individuals but can occasionally cause mild flu-like symptoms. In some cases, it may lead to a mononucleosis-like syndrome, characterised by fever, splenomegaly, and liver function impairment. How is cytomegalovirus infection diagnosed in pregnant women? Diagnosis of maternal cytomegalovirus infection involves viral serology testing for CMV-specific IgM and IgG antibodies. A positive diagnosis is indicated by seroconversion in previously seronegative women or the presence of IgM alongside low IgG avidity. What management options are available for cytomegalovirus infection during pregnancy? Women with confirmed CMV infection should be referred to a fetal medicine specialist. While no treatment is necessary for immunocompetent mothers, fetal infections can be diagnosed via amniocentesis, and if confirmed, there are no effective therapies available, though termination of pregnancy may be considered. What are the potential complications for neonates born with congenital cytomegalovirus infection? Neonates with congenital CMV infection may face serious complications such as intrauterine growth restriction, hepatosplenomegaly, and jaundice. Symptomatic infants have a mortality rate of 20-30%, while those without symptoms have a 10-15% chance of developing complications like hearing loss or developmental delays within two years. Rate This Article