In the United States, about half of expectant mothers have never been infected with CMV. About 1% to 4% of uninfected mothers have primary (or first) CMV infection during their pregnancy. Most women have no symptoms, although some have a disease that is like mononucleosis. About one third of women who become infected with CMV for the first time during pregnancy pass the virus to their unborn babies. Women who had CMV before getting pregnant can also pass the virus to their unborn babies, but this is less common.

Most babies with congenital (meaning from birth) CMV never have health problems. But, in some babies, congenital CMV causes health problems when
the baby is born or later in the baby's life. These health problems may include: hearing loss, bleeding problems, vision loss, liver problems, mental disability, spleen problems, lung problems , and growth problems.

Sometimes health problems such as hearing or vision loss do not occur until months or years after birth. With proper care, most infants with CMV disease survive. Of those with symptoms at birth, 80% to 90% will have problems within the first few years of life. These problems may include hearing loss, vision loss, and various degrees of mental retardation. Of those infants with no symptoms at birth, 5% to 10% will later develop various degrees of hearing and mental or coordination problems.

Pregnant women can be infected with CMV through sexual contact, blood transfusions, and non-sexual, close contact with infected persons, especially young children. Children can be infected with CMV before birth, during delivery, and through breast feeding, blood transfusions, or contact with other children who have CMV. Infants and children who acquire CMV after birth have few, if any, symptoms or problems.

There is no vaccine to prevent CMV infection; however, there are certain steps pregnant women can take that may reduce their risk of acquiring CMV and other infections that may pose a risk to their unborn children. If you are pregnant,

• Wash your hands often with soap and water for 15-20 seconds, especially after changing diapers or touching saliva or nasal secretions from a young child.
• Reduce contact with saliva and nasal secretions from young children by 1) using soap and water or a disinfectant to clean hard surfaces that have been contaminated by secretions, 2) not sharing food, drinks, or eating utensils with young children, and 3) being careful to limit kissing of young children on the lips.

If you work in a day care center, limit close contact with children younger than 2½ years of age, especially if you've never been infected with CMV or don't know if you've been infected.