When your baby is not feeling well or has a health concern, it can be very frightening. Sometimes those health concerns may be related to conditions that developed before birth.

One very common virus that a baby may contract while in the womb is cytomegalovirus (CMV). When a baby gets CMV before birth, it’s known as congenital CMV.

According to the Centers for Disease Control and Prevention (CDC), congenital CMV is the number one infectious cause of sensorineural hearing loss in children. Nearly 1 in 200 babies is born with congenital CMV. Of those, 1 in 5 have lasting health effects, including hearing loss.

Some babies born with congenital CMV who experience hearing loss may have been born with the hearing loss, while others may have developed it during childhood.

Read on to learn more about CMV and sensorineural hearing loss in children.

Sensorineural hearing loss is the most common type of permanent hearing loss, according to the American Speech-Language-Hearing Association.

This type of hearing loss occurs when the inner ear does not develop properly or is injured.

The ear is made of three main parts: the outer ear, middle ear, and inner ear. If a child has congenital CMV, it may affect how the inner ear develops, leading to sensorineural hearing loss.

The inner ear includes a structure called the cochlea which is filled with liquid and has microscopic hairs. As sound waves move into the inner ear, they make the liquid in the cochlea vibrate. This vibration moves the tiny hairs in the cochlea and converts the sound into electrical signals. These signals are then sent through nerves to the brain so you hear the sound.

If any part of the inner ear does not develop or is damaged, sound signals cannot reach the brain, which results in hearing loss.

The signs of sensorineural hearing loss may vary depending on the age of the child and the severity of the hearing loss.

According to the CDC, signs of hearing loss a baby include:

  • has no startle response when loud noises happen
  • doesn’t turn to face a sound after 6 months old
  • isn’t saying single words by 1 year old
  • may appear to hear one sound but not another
  • will turn their head when they see you but not when you call them

Signs of hearing loss in children include:

  • has delayed or unclear speech
  • often asks people to repeat what they said
  • listens to TV or music at a high volume
  • can’t follow simple requests

CMV is a form of the Herpesviridae­­­ virus. It’s a very common infection, and Individuals can contract it at any time. Many people have no symptoms or effects from having CMV.

If a person gets CMV for the first time during pregnancy, it may be passed through the placenta to the baby. When a baby catches CMV while in the womb, it’s called congenital CMV.

CMV can cause hearing loss; however, not every baby or child that gets CMV will have hearing loss. Many babies and children with CMV will have mild symptoms or no symptoms at all.

Even though many people with CMV have no symptoms, CMV remains the leading cause of non-inherited hearing loss.

Babies generally have a newborn hearing evaluation while they are in the hospital after birth. If this screening shows signs of hearing loss, the baby will be checked again and should receive extra testing as they age.

Children who have access to healthcare as they age will also have routine hearing screenings during annual physical exams with their pediatrician. The American Academy of Pediatrics recommends all children have a more extensive hearing screening at ages 4, 5, 6, 8, and 10. Children with signs of hearing loss need more frequent screening.

A hearing evaluation for an infant or child with hearing loss from CMV may include these tests:

Automated auditory brainstem response (AABR)

This test uses a computer, electrodes attached to your child’s head, as well as a wand or headphones that deliver sound into your child’s ear. The AABR test measures the markers or responses your child’s brain does or does not make to these sounds.

Otoacoustic emissions (OAE)

This test is used for children who cannot respond, so it is given to babies and very young children. The OAE test uses small earphones inserted into the ear. Clicking sounds are sent into the ear.

When the sounds reach the cochlea, if they vibrate the tiny hairs, very faint sounds called otoacoustic emissions will bounce back to the middle ear. There, the earphone will measure them.

A hearing evaluation for a child may include AABR, OAE, and other tests such as:

Behavioral audiological evaluation

This test measures how a child responds to sounds at various levels. It is usually conducted in a soundproof booth or room, and a child will either look toward a sound or be asked to respond when they hear a sound.


This test uses a puff of air delivered into the ear to move the ear drum while a machine records the movements. Since the child needs to sit still for this test, it is usually not given to very young children.

Tuning fork tests

Tuning fork tests literally use a tuning fork to help determine if there is hearing loss and if the hearing loss is sensorineural. There are two tuning fork tests:

  • Weber’s test. In this test, a tuning fork is struck and placed in the middle of the child’s forehead. If the sound is louder in an ear that does not have hearing loss, then the hearing loss present in the other ear is likely sensorineural hearing loss.
  • Rinne test. This test is used primarily to identify conductive hearing loss. In this test, the tuning fork is struck and placed against the bone behind the ear until the sound stops, then the fork is moved in front of the ear canal. If the sound is heard or is louder in front of the ear, hearing loss is likely sensorineural. If the sound is heard longer on the bone, the cause of hearing loss is likely conductive.

While there is no cure for sensorineural hearing loss, some children diagnosed with congenital CMV at birth may benefit from antiviral medication. This, according to the CDC, may help reduce the severity of sensorineural hearing loss caused by CMV.

Some options may help children with sensorineural hearing loss, including:

Cochlear implants

Cochlear implants are devices that send signals to the cochlear nerve and help restore sound and speech perception to people with sensorineural hearing loss. The device is made up of two parts:

  • a receiver, called an electrical array, that is implanted inside the inner ear
  • a microphone or transmitter that is worn behind the ear

Children who are born with sensorineural hearing loss may have a cochlear implant placed when they are very young — between 6 months and 1 year sometimes.

Hearing aids

Hearing aids are devices that help make sounds louder or change sounds so that they may be heard by some children with sensorineural hearing loss. There are several different types of hearing aids, but most are worn over the ear.

Bone conduction hearing devices

These devices, sometimes called bone anchored hearing aids (BAHA), may be used to help children with some types of sensorineural hearing loss. They send sound through bone to the middle and inner ear. They may be surgically implanted, magnetic, or worn as an external wrap.

Other therapies

In addition to devices to help improve hearing, children with sensorineural hearing loss may benefit from services and training to help improve their communication skills, such as:

It’s important that children with hearing loss receive services as early as possible to help ensure they develop good social and communication skills.

Some children who have congenital CMV may have hearing loss at birth, while others may develop it later in childhood or later in their lives.

Children with congenital CMV may benefit from antiviral medications. For some children, antiviral medications may help reduce the level of sensorineural hearing loss they have, per the CDC.

Sensorineural hearing loss is permanent, but certain devices may help improve hearing.

Congenital CMV is the leading cause of non-inherited sensorineural hearing loss in infants. Children who have CMV are at risk for hearing loss either at birth or as they age. They should have routine hearing screens throughout their lives.

Sensorineural hearing loss cannot be cured, but options such as hearing aids, cochlear implants, and others can help improve hearing. Children with sensorineural hearing loss will also benefit from therapies to help improve their communication and social skills.