Congenital Cytomegalovirus (CMV) Infection
What is Congenital Cytomegalovirus (CMV) Infection?
Congenital cytomegalovirus infection happens when a baby is infected with CMV before birth. CMV is a common virus in the herpes family that most adults carry without knowing it. When a pregnant woman gets infected with CMV for the first time or has a reactivation of the virus, it can pass through the placenta to the developing baby.
Most babies born with congenital CMV appear healthy at birth. About 1 in 200 babies is born with this infection in the United States. Of those, only 1 in 5 will develop symptoms or long-term health problems. However, congenital CMV remains the most common viral infection passed from mother to baby during pregnancy.
The infection can affect different organ systems in the developing baby. Early detection and monitoring help families prepare for potential challenges and connect with appropriate medical care and support services.
Symptoms
- Small head size at birth, known as microcephaly
- Premature birth or low birth weight
- Jaundice, or yellowing of the skin and eyes
- Enlarged liver and spleen
- Purple skin spots or rash
- Seizures or other neurological problems
- Hearing loss that may not appear until later in childhood
- Vision problems or damage to the retina
- Poor feeding or difficulty sucking
- Developmental delays or intellectual disabilities
About 80 to 90 percent of babies with congenital CMV show no symptoms at birth. These babies can still develop hearing loss or other problems months or years later. This is why testing and follow-up care matter even when a baby appears healthy.
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Causes and risk factors
Congenital CMV happens when a pregnant woman is infected with cytomegalovirus and passes it to her baby. The virus can cross the placenta at any stage of pregnancy. Women who get infected with CMV for the first time during pregnancy have a higher risk of passing it to their baby. Women who had CMV before pregnancy can also pass it on if the virus reactivates, though this usually causes milder infections in babies.
Risk factors include close contact with young children, especially in daycare settings, since toddlers often carry and spread CMV through saliva and urine. Working in childcare or healthcare settings increases exposure risk. Having multiple sexual partners also raises the chance of infection. Women with weakened immune systems face higher risks of reactivation. Most pregnant women who pass CMV to their babies had no idea they were infected because CMV rarely causes noticeable symptoms in healthy adults.
How it's diagnosed
Congenital CMV is diagnosed through specialized testing of newborns within the first three weeks of life. Doctors can test saliva or urine samples from the baby to detect the virus. Blood tests can look for CMV antibodies, including IgM antibodies that may indicate a recent or active infection. Testing must happen early because a positive test after three weeks cannot confirm congenital infection versus infection acquired after birth.
Some hospitals now screen all newborns who fail their hearing tests for CMV. Pregnant women concerned about CMV exposure can also be tested through blood work to check their antibody status. Talk to your doctor about specialized CMV testing if you are pregnant or have a newborn with symptoms. These tests require specific ordering and may not be part of routine prenatal or newborn screening.
Treatment options
- Antiviral medication, such as valganciclovir, for babies with symptoms or severe infection. Treatment usually lasts six months.
- Hearing tests every three to six months during the first years of life, even for babies without symptoms at birth.
- Vision exams to check for eye problems related to CMV.
- Physical therapy and occupational therapy to support development if delays occur.
- Speech therapy to help with language development and communication.
- Early intervention programs that provide support services for infants and toddlers with developmental needs.
- Hearing aids or cochlear implants if hearing loss develops.
- Regular developmental screenings to catch problems early.
Frequently asked questions
Congenital CMV infection occurs when a baby gets cytomegalovirus from their mother during pregnancy. The virus crosses the placenta and infects the developing baby. Most babies with congenital CMV appear healthy at birth, but some may have serious complications. It is the most common viral infection passed from mother to baby before birth.
About 1 in 200 babies in the United States is born with congenital CMV infection. This makes it more common than many conditions that are routinely screened for at birth. Only about 20 percent of infected babies show symptoms at birth. The condition causes more childhood hearing loss than any other single infectious disease.
Pregnant women can reduce their risk by practicing good hygiene, especially around young children. Wash hands thoroughly after changing diapers or wiping noses. Avoid sharing food, drinks, or utensils with young children. Do not put a pacifier in your mouth before giving it to a baby. These steps help prevent initial infection or reactivation during pregnancy.
Long-term effects vary widely depending on the severity of infection. Some children develop hearing loss that may progress over time. Others may have vision problems, developmental delays, or learning disabilities. Severe cases can cause seizures, intellectual disabilities, or problems with coordination. Many children with congenital CMV grow up healthy without any lasting problems.
Testing must be done within the first three weeks of life using saliva or urine samples from the baby. Doctors can also check blood for CMV antibodies, including IgM antibodies that suggest active infection. Testing after three weeks cannot confirm congenital infection because babies can catch CMV after birth. Early testing is critical for accurate diagnosis.
Routine CMV screening is not currently recommended for all pregnant women in the United States. However, women who work with young children or have concerns about exposure can ask their doctor about testing. Blood tests can show if a woman has had CMV before or has a new infection. Talk to your healthcare provider about whether testing makes sense for your situation.
Babies with symptoms or severe infection may be treated with antiviral medications like valganciclovir for six months. Treatment can improve hearing and developmental outcomes. All babies with congenital CMV need regular hearing tests and developmental monitoring. Early intervention services provide therapy and support for children who develop delays or disabilities.
Yes, most women with CMV have healthy babies without any problems. Women who had CMV before pregnancy have a much lower risk of passing severe infection to their baby. Even when babies are infected, 80 to 90 percent have no symptoms at birth. Regular prenatal care and good hygiene practices help reduce risks.
CMV can damage the inner ear structures that process sound. Hearing loss can be present at birth or develop later in childhood. It may affect one or both ears and can get worse over time. This is why all children with congenital CMV need regular hearing tests, even if they passed their newborn hearing screening.
Early intervention programs provide free or low-cost services for infants and toddlers with developmental needs. These include physical therapy, speech therapy, and special education support. Support groups connect families dealing with similar challenges. Your pediatrician can refer you to specialists like audiologists, neurologists, and developmental pediatricians who understand congenital CMV.