Cytomegalovirus (CMV) is a virus that can be transmitted to a developing child before birth. CMV
infection is usually harmless and rarely causes illness. For most healthy persons who acquire CMV after
birth, there are few symptoms and no long-term health consequences. Once a person becomes infected, the virus
remains alive, but usually dormant within that person’s body for life. There are two different types of infection:
primary CMV and recurrent CMV infection. Primary infection can cause more serious problems in pregnancy than
recurrent infection can. However, if a person's immune system is seriously weakened in any way, the virus can
become active and cause CMV disease. For the majority of people who have CMV infection, it is not a serious
What are the symptoms of CMV?
Most children and adults who are infected with CMV do not develop symptoms, whereas others may
experience the following symptoms three to twelve weeks after exposure:
Exhausted or run down
What are characteristics of CMV?
CMV is a member of the herpes virus group that is characterized by the ability to remain dormant
within the body over a long period. Infectious CMV may be shed in bodily fluids (urine, saliva, blood, tears,
semen, and breast milk) intermittently, without any detectable signs and without symptoms.
How common is CMV?
Infects between 50% and 85% of adults in the United States by 40 years of
Is more widespread in developing countries and in areas of lower socioeconomic conditions
Is higher among the following risk groups:
babies in utero
people who work with children
immunocompromised persons, such as organ transplant recipients and persons infected with human
immunodeficiency virus (HIV)
How is CMVspread?
Transmission of CMV occurs from person to person and is not associated with food, water, or
animals. CMV is not highly contagious but has been shown to spread in households and among young children in day
care centers. The infection is spread through close, intimate contact with a person excreting the virus in their
saliva, urine, breast milk or other bodily fluids.
How is CMV diagnosed?
Most CMV infections are rarely diagnosed because the virus usually produces few, if any,
symptoms. However, people who have had CMV develop antibodies to the virus which remain in their body for the rest
of their life. A blood sample can test for the CMV antibody, followed by another blood sample within two weeks. The
virus can also be cultured from specimens obtained from urine, throat swabs, and tissue samples. Laboratory tests
to culture the virus are expensive and not widely available.
If a pregnant woman is diagnosed with the CMV infection, there are a few ways that the fetus can
be checked for infection. Amniocentesis can be done to check fetal fluids or blood for signs of infection. Symptoms
that could signify possible infection include low amniotic fluid levels, intrauterine growth restriction, and
enlarged tissues in the brain. Once the baby is born, testing can be done by saliva, urine, or blood.
What is the treatment for CMV?
Maternal CMV infections may be treated with one of two drugs that are used in severe situations
of CMV infection. There are no treatments for prenatal or postnatal therapy of the infection. Vaccines for
treatment are still in the research and developmental stages.
How can CMV be prevented?
Transmission of cytomegalovirus is often preventable because it is most often transmitted
through infected bodily fluids that come in contact with hands and then are absorbed through the nose or mouth of a
susceptible person. People who interact with children should use safe hygiene practices including good hand washing
and wearing gloves when changing diapers. Hand washing with soap and water is effective in preventing the spread of
How does CMV affect pregnancy?
Pregnant women who are healthy are not at special risk for disease from CMV infection. In fact,
the incidence of primary maternal CMV infection in pregnant women in the United States varies from 0.7% to 4%.
Pregnant women who are infected with CMV rarely have symptoms, but rather their developing baby may be at risk for
congenital (meaning from birth) CMV disease. CMV is the most common cause of congenital viral infection in the
United States. The transmission rate to the fetus is between 24-75% according to the Organization of Teratology
Information Service (OTIS), with an average transmission rate of 40%. Of the 40% of babies who become infected,
only 10% show signs of congenital CMV after primary maternal infection. For women who have been infected at least 6
months prior to conception, the rate of newborn CMV infection is about 1%, and these infants appear to have no
significant illness or abnormalities.
The following potential problems can occur for infants who are infected from their mothers
before (during pregnancy) birth:
Moderate enlargement of the liver and spleen
80-90% suffer from complications within the first few years of life including hearing loss, vision
impairment, and varying degrees of mental retardation.
5-10% will present with no symptoms at birth but will develop varying degrees of hearing and mental or
When CMV is transmitted at the time of delivery from contact with genital secretions or later in
infancy through breast milk, these infections usually result in few, if any, symptoms or complications.
What are some recommendations for pregnant women regarding CMV
Throughout your pregnancy practice good personal hygiene, including hand
washing with soap and water
If you develop a mononucleosis-like illness, you should be checked for CMV infection
Refrain from sharing food, eating utensils and drinking utensils with anyone.
Your doctor can test the CMV antibodies to determine if you have already had CMV infection.
Breastfeeding benefits outweigh the minimal risk of transmitting CMV
What are some recommendations for individuals who care for infants and
children regarding CMV infection?
Most healthy people working with infants and children are not at risk of CMV infection. However,
women of child-bearing age who previously have not been infected with CMV still have a potential risk of passing
CMV to their babies in utero. CMV is commonly transmitted among young children. Since CMV is transmitted through
contact with infected bodily fluids, including urine and saliva, child care providers (including day care workers,
special education teachers, and therapists) should be educated about CMV infection and practice preventive
measures. Susceptible non-pregnant women working with infants and children should not routinely be transferred to
other work situations. Routine laboratory testing for the CMV antibody in female workers is not recommended, but
can be performed to determine their immunity status.