Although the majority of adults will have been infected with CMV by the age of 40 years, 30-50% of women of childbearing age remain susceptible to CMV infection. The incidence of primary CMV infection in pregnant women in the United States varies from 1% to 4%. Healthy pregnant women are not at special risk for disease from CMV infection; however CMV can pass to the developing fetus and cause congenital CMV infection.
Most people have no symptoms when they become infected with CMV, but some may experience a mononucleosis-like syndrome with prolonged fever and a mild hepatitis. Pregnant women with symptoms of mononucleosis should be evaluated for CMV infection.
Cytomegalovirus remains the most important cause of congenital viral infection in the United States. The risk of serious complications from CMV infection is highest among the infants born to women who had a primary CMV infection during pregnancy. However, even among women who have their first infection during pregnancy, two thirds will have infants who are not born with congenital CMV infection.
TThere appears to be little risk of CMV-related complications in infants born to mothers who were infected 6 months or more before conception. This group makes up the majority (50%-80%) of women of child-bearing age in the United States. Among women who were infected with CMV 6 months or more before becoming pregnant, the rate of congenital CMV infection in their infants is approximately 1%, and significant illness or abnormalities among these infants appears to be less common than in infants with congenital CMV infection born to women who had a primary CMV infection during pregnancy. (See How Many Babies Are Affected by Congenital CMV Infection?)
Since CMV is transmitted through contact with infected body fluids, including urine and saliva, contact with young children who are shedding CMV may be a source of exposure to the virus. Pregnant women who have close contact with young children, such as childcare providers and family members, appear to be at a greater risk of CMV infection than persons who do not have ongoing contact with children. Healthcare providers who work with infants and children do not appear to have a higher rate of CMV infection; this may be due, at least in part, to standard precautions in place to prevent transmission of infections in healthcare settings. Also see general information on People Who Care for Infants and Children.
Recommendations for pregnant women with regard to CMV infection are summarized below:
- Pregnant women should follow the hygiene practices outlined in the Prevention section. These steps may reduce a woman’s risk of exposure to CMV and other infections that might pose a risk to her pregnancy.
- Women who develop a mononucleosis-like illness during pregnancy should be evaluated for primary CMV infection.
- Recovery of CMV from the cervix or urine of women at or before the time of delivery does not warrant a cesarean section.
- In most cases, the demonstrated benefits of breast-feeding by CMV-positive mothers outweigh the minimal risk of acquiring CMV from the breast milk. Physicians and mothers should take into account the potential risk of transmitting CMV when making decisions about breast-feeding very premature infants.
Also see general information on Pregnant Women.
Guidelines for Obstetricians and Gynecologists
The guidelines are available at American Congress of Obstetricians and Gynecologists (ACOG) Web site: Perinatal viral and parasitic infections. Washington (DC): ACOG; 2000 Sep. 13 (ACOG practice bulletin; no. 20). [131 references]
Primary CMV infection in the immunocompromised patient can cause serious disease, however, this is less common than reactivation of the dormant virus. CMV is a major cause of disease and death in immunocompromised patients, including organ transplant recipients, patients with lymphoid cancers, and HIV-infected patients. Pneumonia, retinitis, and gastrointestinal disease are the common manifestations of disease. Because of this risk, exposure of immunosuppressed patients or persons expected to become immunosuppressed to outside sources of CMV should be minimized.
Also see People with Weakened Immune Systems.
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