My Baby Has Congenital CMV (Cytomegalovirus)
The short answer
Congenital cytomegalovirus (CMV) infection occurs when CMV is passed from mother to baby during pregnancy. It is the most common congenital infection, affecting about 1 in 200 babies. Most babies with congenital CMV (about 90%) have no symptoms at birth and do well. However, about 10% are symptomatic at birth and may have hearing loss, vision problems, developmental delays, or other complications. CMV is also the leading non-genetic cause of hearing loss in children. Early identification and antiviral treatment can improve outcomes for symptomatic babies.
Parents everywhere have the same worry. You are doing the right thing by looking into it.
By Age
What to expect by age
0-1 month (diagnosis)
Congenital CMV must be diagnosed within the first 3 weeks of life (by testing urine or saliva) to distinguish it from CMV acquired after birth. Symptomatic babies may have petechiae (tiny red spots), jaundice, small head size, enlarged liver or spleen, or abnormal brain imaging. If your baby is diagnosed with symptomatic congenital CMV, antiviral treatment (valganciclovir) started within the first month of life has been shown to improve hearing and developmental outcomes.
1-6 months
For symptomatic babies, antiviral treatment typically continues for 6 months. Blood counts and liver function are monitored during treatment, as the medication can cause side effects. Hearing tests should be performed at diagnosis and repeated regularly, because CMV-related hearing loss can fluctuate or worsen over time — even in babies who initially pass their newborn hearing screen.
6-12 months
Both symptomatic and asymptomatic congenital CMV babies need regular hearing monitoring. About 10-15% of babies who had no symptoms at birth will develop hearing loss, often during the first year of life. If hearing loss is detected, early hearing aids or cochlear implants can make a significant difference in speech and language development. Developmental assessments are also recommended.
1 year+
Children with congenital CMV should have hearing monitored through at least age 6, as late-onset hearing loss can occur. Those with hearing loss benefit from early intervention services, hearing aids, or cochlear implants. Many children with congenital CMV, even those who were symptomatic, develop well with appropriate support. Speech therapy and educational support may be needed for children with hearing-related language delays.
What Should You Do?
When to take action
- Your baby was diagnosed with congenital CMV but had no symptoms at birth and is developing normally — most asymptomatic babies do well
- Your baby is receiving antiviral treatment and is tolerating it well with regular monitoring
- Your baby's hearing tests have been normal so far and you are continuing regular follow-up
- Your baby seems to not respond to sounds or voices as expected
- Your baby is not babbling by 6 months or has concerns about speech development
- Your baby had congenital CMV and is not meeting developmental milestones
- You are pregnant or planning another pregnancy and have questions about CMV prevention
- Your baby on antiviral treatment develops a high fever, unusual bruising, or looks pale — these may be medication side effects requiring immediate blood work
- Your baby has seizures or sudden developmental regression — seek emergency medical evaluation
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
Worrying about your baby means you care. That is a good thing.
Related Medical Concerns
My Baby Has Auditory Neuropathy — What Does This Mean?
Auditory neuropathy spectrum disorder (ANSD) is a hearing condition where the inner ear (cochlea) detects sound normally, but the signal is not transmitted properly to the brain via the auditory nerve. This means your baby may pass one type of hearing test (OAE) but fail another (ABR). ANSD affects about 10-15% of children diagnosed with permanent hearing loss. The hearing ability of children with ANSD is highly variable — some hear almost normally, others have severe hearing loss, and hearing can fluctuate. Early intervention with hearing aids or cochlear implants, combined with speech therapy, gives the best outcomes.
How Dangerous Is My Baby's Jaundice? (Kernicterus Prevention)
Jaundice (yellowing of the skin from bilirubin) is extremely common in newborns — about 60% of term and 80% of preterm babies develop it. Most jaundice is harmless and resolves with or without phototherapy. However, very high bilirubin levels can cross into the brain and cause permanent damage (kernicterus), including cerebral palsy, hearing loss, and intellectual disability. Kernicterus is almost entirely preventable with appropriate monitoring and treatment. The key is ensuring bilirubin levels are checked per guidelines and treated promptly when elevated.
My Baby's Head Shape Looks Abnormal
Many babies develop temporary head shape irregularities that are completely normal. A cone-shaped head from vaginal delivery reshapes within days. Mild positional flattening (plagiocephaly) from sleeping on the back is very common and usually improves with repositioning and tummy time. However, head shape changes involving ridges, a persistently bulging fontanelle, or rapid head growth changes should be evaluated to rule out craniosynostosis.
Achondroplasia (Dwarfism) in Babies
Achondroplasia is the most common form of short-limbed dwarfism, affecting about 1 in 15,000 to 40,000 births. It is caused by a mutation in the FGFR3 gene and is usually apparent at birth with characteristic features including short limbs, a larger head, and a prominent forehead. Intelligence is normal. With monitoring for specific complications and supportive care, children with achondroplasia lead full, active, and independent lives.
Adenoid Hypertrophy and Breathing
Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.
How to Advocate for Your Child's Needs
You know your child better than anyone, and your observations matter. If you feel something is not right with your child's development or health, you have every right to ask questions, request evaluations, and seek second opinions. Advocating for your child is not being difficult - it is being a good parent.