Congenital Cytomegalovirus

Cytomegalovirus, or CMV, is a common infection that is caused by the human herpesvirus-5 (HHV-5). Congenital CMV is CMV that is present before birth. Although many people who get cytomegalovirus will experience mild, if any, symptoms, the virus can be dangerous if passed to a fetus through the placenta during pregnancy.

Congenital cytomegalovirus is the most common infectious cause of birth defects in the United States, according to the Centers for Disease Control. In the United States, 1 in 200 babies born is infected with CMV. Of these babies, 1 of every 5 born with CMV will have birth defects or long-term health support needs. 

CMV is a highly contagious virus that easily spreads from person to person through contact with infected bodily fluids, so many people are exposed at some point just living their lives. Because CMV infections are often without symptoms (asymptomatic), they can be easily spread through household contacts and childcare settings. Experts estimate that about half of people in the United States will have had CMV by the time they reach age 40.  

Some people are at greater risk for a symptomatic CMV infection, including:

• Young children who attend childcare centers.
• Pregnant women, especially those living with young children who attend childcare/early education centers.
• People who are immunocompromised—whether because of an underlying condition, another infection, an organ transplant, or any other reason.

If you are pregnant and get cytomegalovirus, it is possible to pass the virus to your fetus through your placenta. Congenital CMV (cytomegalovirus that is present before birth) can cause complications such as developmental delay and hearing loss in babies. CMV may also be passed to your child through breastmilk.

Congenital CMV infection and its related complications can happen regardless of which trimester of pregnancy you contract the virus. However, the most severe infant complications are more commonly associated with maternal infection during the first trimester. 

Most CMV infections are asymptomatic (without symptoms), particularly in children; however, the virus can still be spread from person to person without the presence of symptoms. When CMV infection is associated with symptoms, they may include fever, fatigue, swollen glands, achiness, sore throat, and rash.  

People who have otherwise healthy immune systems may not experience any symptoms, and their bodies can usually clear the virus on their own.

Congenital CMV can have a variety of symptoms; however, symptoms are often not evident at birth—this is known as asymptomatic congenital CMV infection.

Congenital cytomegalovirus can cause the following in newborn babies:

• Anemia
• Low birth weight
• Yellow skin or eyes (jaundice)
• Hearing loss or deafness
• Epilepsy and seizures
• Smaller than typical head size (microcephaly)
• Delays in motor development
• General developmental delay
• Cerebral palsy
• Delay or difference in development of the brain, lungs, liver, or spleen

Only about 10% of infants born with congenital CMV will show symptoms at birth. Early detection and intervention is crucial in the management of congenital CMV, which is why screening for CMV has recently been added to the routine newborn screening panel.

Cytomegalovirus is diagnosed on the newborn screening panel through blood. CMV can also be diagnosed in infants through lab tests of bodily fluids like urine, saliva, or cerebrospinal fluid (CSF). Some states—including Minnesota—have recently (as of 2023) added CMV infection as part of their newborn screening panel. This means that any baby born in Minnesota is automatically tested for congenital CMV shortly after birth.

Note: congenital cytomegalovirus infection requires diagnosis within the first three weeks of life. Detection of CMV after this initial period could represent post-natal viral infection.

After diagnosis of congenital CMV, treatment is often recommended with an antiviral medication for up to 6 months. Although birth defects or complications of congenital CMV infection cannot be reversed, early treatment of newborns with confirmed congenital CMV infection have shown improved hearing and neurodevelopmental outcomes by 2 years of age compared to those who do not receive treatment.  Long term, babies born with congenital CMV can benefit from the care of a multidisciplinary medical team as they grow older and need support with complications such as neurodevelopmental delays, seizures, delayed motor development, hearing loss, delayed speech, and others. 

Gillette Children’s offers a multidisciplinary team of pediatric experts trained to care for infants, babies, and children experiencing long-term effects of infections like congenital cytomegalovirus.

When you entrust Gillette Children’s with your child’s care, they will enjoy access to the foremost experts in:

• Infectious disease  
• Audiology
• Complex care
• Pediatric neurology
• Occupational therapy
• Physical therapy
• Speech therapy
• Pediatric physical medicine and rehabilitation

The team at Gillette Children’s works with your family every step of the way to make sure your child receives the individualized, high-quality care they need to thrive throughout their life.