Congenital CMV Infection
What is Congenital CMV infection?
Congenital CMV infection happens when a baby gets cytomegalovirus from their mother during pregnancy. CMV is a common virus that usually causes no problems in healthy adults. When a pregnant woman gets infected with CMV for the first time, the virus can cross the placenta and reach the developing baby.
Most babies born with congenital CMV infection show no symptoms at birth. About 1 in 200 babies is born with this infection in the United States. Around 20% of infected babies will develop health problems that can appear at birth or later in childhood. These problems can affect hearing, vision, brain development, and growth.
CMV is part of the herpes virus family. It stays in the body for life after infection. A mother who had CMV before pregnancy can rarely pass it to her baby, but the risk is much lower than with a first-time infection during pregnancy.
Symptoms
Many babies with congenital CMV infection appear healthy at birth. When symptoms do occur, they can include:
- Small size at birth or low birth weight
- Small head size, a condition called microcephaly
- Enlarged liver and spleen
- Yellow skin and eyes, known as jaundice
- Purple skin spots or rash
- Seizures or unusual movements
- Feeding difficulties or poor muscle tone
- Hearing loss that may appear later
- Vision problems or eye inflammation
About 80% of babies with congenital CMV show no symptoms at birth. Some children develop hearing loss or developmental delays months or years later, even without early symptoms.
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Causes and risk factors
Congenital CMV infection occurs when a pregnant woman passes cytomegalovirus to her unborn baby. The virus spreads through body fluids like saliva, urine, blood, tears, breast milk, and genital fluids. A mother can get CMV through close contact with young children, sexual contact, or exposure to infected fluids. Pregnant women who work in childcare or have young children at home face higher risk.
The greatest risk to the baby happens when a mother gets her first CMV infection during pregnancy. About 1 in 3 babies will be infected if the mother gets CMV while pregnant. Women who had CMV before pregnancy can experience reactivation of the virus, but this rarely causes severe problems for the baby. The earlier in pregnancy the infection occurs, the more serious the potential effects on the developing baby.
How it's diagnosed
Doctors diagnose congenital CMV infection by testing a baby's saliva, urine, or blood within the first 3 weeks of life. Testing after 3 weeks cannot confirm whether the infection was present at birth or acquired later. Blood tests can detect CMV antibodies, including IgM antibodies that suggest recent infection. Hearing and vision tests help identify problems that CMV can cause.
Pregnant women are not routinely tested for CMV in the United States. Testing may be recommended if a woman shows symptoms of infection or if an ultrasound shows signs that suggest CMV in the baby. Talk to a healthcare provider about specialized testing options if you have concerns about CMV exposure during pregnancy or suspect your baby may have been exposed.
Treatment options
Treatment approaches depend on the severity of symptoms and include:
- Antiviral medications like ganciclovir or valganciclovir for babies with symptoms
- Hearing aids or cochlear implants for children with hearing loss
- Vision therapy or corrective lenses for eye problems
- Physical therapy to support motor development
- Speech therapy to address language delays
- Educational support and early intervention services
- Regular monitoring with hearing tests every 6 months through early childhood
- Developmental screenings to catch delays early
Antiviral treatment is most effective when started within the first month of life. Children with congenital CMV need ongoing care from specialists including audiologists, ophthalmologists, and developmental pediatricians. Early intervention services can make a significant difference in long-term outcomes.
Frequently asked questions
Pregnant women can reduce their risk by washing hands frequently, especially after contact with young children's saliva or urine. Avoid sharing food, drinks, or utensils with young children. Do not put a child's pacifier in your mouth. These simple hygiene steps can significantly lower the chance of getting CMV during pregnancy.
About 1 in 200 babies is born with congenital CMV infection in the United States. This makes it the most common congenital infection. Most infected babies show no symptoms, but roughly 1 in 5 will develop health problems. Hearing loss is the most common long-term effect.
No, about 80% of babies born with CMV show no symptoms and develop normally. Among those who do have symptoms, the severity varies widely. Some children have mild issues while others face more serious challenges. Regular monitoring helps catch and address problems early when treatment is most effective.
Yes, but routine screening is not standard in the United States. Doctors may test pregnant women who have symptoms of infection or if an ultrasound shows concerning signs. Blood tests can check for CMV antibodies. Amniocentesis can test the amniotic fluid to see if the baby is infected, though this carries some risks.
IgM antibodies are proteins your immune system makes when first fighting a new infection. CMV IgM in a baby's blood suggests recent or active CMV infection. This test helps doctors determine if a baby has congenital CMV. IgM antibodies typically appear within weeks of infection and fade over time.
Universal newborn CMV screening is not currently standard practice in most places. Some states are beginning to screen babies who fail newborn hearing tests. Testing is recommended for babies who show symptoms of possible CMV infection at birth. Early diagnosis allows for prompt treatment and monitoring.
For full-term healthy babies, the benefits of breastfeeding outweigh the small risk of CMV transmission through breast milk. Premature babies may be at higher risk and doctors may recommend special precautions. Talk to your pediatrician about your specific situation. The decision should consider both the baby's health status and the mother's CMV status.
The infection itself does not worsen, but some effects may not appear until later in childhood. Hearing loss can develop or progress in the first few years of life even in children without symptoms at birth. This is why regular hearing tests are important for all children born with CMV, regardless of early symptoms.
No CMV vaccine is currently available, though several are in development and clinical trials. Prevention focuses on good hygiene practices, especially for pregnant women around young children. Researchers consider CMV vaccine development a high priority because of how common and serious congenital infection can be.
Yes, children with congenital CMV can safely attend school and daycare. CMV spreads through close contact with body fluids, but standard hygiene practices used in childcare settings provide adequate protection. Children with CMV are not more contagious than other children who may have the virus. Some may need extra support services for hearing, vision, or developmental needs.