Cytomegalovirus infection in pregnancy - An update.

Cytomegalovirus (CMV) is a ubiquitous DNA virus with a global seroprevalence of 83 %. It is the most common pathogen causing teratogenic congenital infection. It is therefore a major public health concern. Maternal infection is associated with congenital CMV (cCMV), the leading cause of non-genetic sensorineural hearing loss. cCMV also causes impairment of cognitive development and cerebral palsy. Transmission of CMV occurs through direct contact with bodily fluids such as saliva, urine or semen from someone who is actively shedding the virus. Transmission rates are higher after primary infection with the rate of transmission increasing with gestational age. Severe fetal effects are however more common when infection occurs before 20weeks. Past infection does not confer immunity to mother or protect the fetus. cCMV may present with cerebral or extracerebral abnormalities on ultrasound, fetal growth restriction and fetal loss. Diagnosis of primary maternal CMV in pregnancy should be based on seroconversion in pregnancy (de novo appearance of virus-specific immunoglobulin G (IgG) in the serum of pregnant women who were previously seronegative) or on detection of specific immunoglobulin M (IgM) and IgG antibodies in association with low IgG avidity. Prenatal diagnosis of fetal CMV is imperfect and based on amniocentesis performed at least 8 weeks after presumed maternal infection and after 17 weeks of gestation. Hygiene information and education of pregnant women is currently the most effective strategy for prevention of CMV infection. The role of vaccines, antiviral drugs and immunoglobulins remains unproven.