Congenital Cytomegalovirus (CMV)

Cytomegalovirus (sy-toh-mega-loh-virus), or CMV, is a common virus that causes cold-like symptoms. It does not harm most people and may cause a few days of sore throat and feeling tired. CMV stays silent in the body and can become active from time to time. There are different types of CMV. If a person catches CMV right before becoming pregnant or during pregnancy, or a previous infection becomes active, their fetus may get CMV. Babies that get CMV during pregnancy are referred to as having congenital CMV, or cCMV.

About one in every 200 babies born in the United States has cCMV.

Most babies with cCMV have no signs you can see at birth. About 10–20% of babies born with cCMV will have more serious problems. At birth they may have a low birth weight and/or small head size (microcephaly). They may also have other signs at birth such as hearing loss, feeding difficulties, jaundice, and a purple spotted rash. Congenital CMV can also lead to long-term health problems, like later hearing loss and developmental delay. Common health problems associated with cCMV are listed in the box, below.

CMV is transmitted through body fluids, like saliva, urine, and semen. People who catch CMV can pass the virus to others for months. Young children, especially those in daycare or preschool, often have CMV in their body fluids. If a pregnant person gets those infected body fluids in their body (e.g. by kissing), they may get CMV and their baby may develop cCMV.

People who spend time with young children are at a higher risk of catching CMV and having a baby with cCMV. This includes people with young children, and those who work with young children such as daycare workers, teachers, and other health care providers. People who have had CMV can catch it again and pass it to their baby during pregnancy.

Only one-third of people who catch CMV while pregnant pass it to their baby. Most people who catch CMV while pregnant do not have babies with cCMV.

Some health care providers may offer routine testing for CMV antibodies at the beginning of the pregnancy. This is to find out if you have ever had a CMV infection, or if you have a current infection. Others may offer testing if you think you may have been exposed, or for those who spend time with young children. Your health care provider may also recommend CMV testing if certain results are seen on ultrasound, such as slow growth, smaller head size, or other signs of infection.

Your health care provider may recommend some blood tests for antibodies or discuss testing your amniotic fluid.  This is to see if your baby has the virus. Ultrasounds can monitor the baby's growth and look for other signs of congenital CMV, like slow growth or small head size.

There are no known treatments for cCMV during pregnancy. In the United States, anti-viral medication or treatment with immunoglobulins are not recommended. Research has not found these treatments safe or effective for the baby.

Yes, you can have a vaginal birth if your baby is growing well and there are no concerns for extra bleeding after the birth.

No, at present babies are not all tested for cCMV. Some health centers will test all babies for cCMV who do not pass their newborn hearing test. A few states have begun screening all babies.

After your baby is born, you can hold your baby skin-to-skin, cuddle, and breastfeed your baby if you wish. As long as your baby is doing well, there is no need for them to have special testing in the first hours of life. Your baby's care provider may test the saliva or urine for CMV, to see if your baby has cCMV. If your baby does have cCMV they will have their hearing and vision checked. Your baby's care provider may recommend talking to a specialist about potential medication for your baby.

Most babies with cCMV who appear healthy at birth do not develop hearing loss or developmental issues. Some babies may develop signs over time, such as hearing loss (10-15%), developmental delay (1-2%) and minor vision loss (2%). Monitoring your baby's hearing and development over time will be important.

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