Risk Factors for Hearing Loss at Birth in Newborns with Congenital Cytomegalovirus Infection

In the United States, about one out of every 200 babies are born with congenital cytomegalovirus (cCMV), and nearly one in three children are infected with cCMV by age five. cCMV is the most common infectious cause of birth defects in the United States.

Unfortunately, one in five babies with cCMV will have symptoms or long-term health problems, such as hearing loss. Some babies with cCMV who have no signs of disease at birth still may have or eventually develop hearing loss in one or both ears. Progression of the hearing loss can occur through adolescence. (CDC, 2018).

cCMV continues to be one of the leading causes of congenital nonhereditary sensorineural hearing loss. Yet, despite a large amount of research on the subject, it remains unclear which newborns born with cCMV are at risk for hearing loss. In addition, only 11 states have laws in place to mandate education, hearing screening, or both, although some states are in the progress of passing legislation. 

Dr. De Cuyper and colleagues (2022), representing 10 facilities across Belgium, completed a cross-sectional study of newborns with cCMV infection over 15 years (January 1, 2007, to February 7, 2022). Patients had a confirmed diagnosis of cCMV infection and known hearing status. Infants with other possible causes of sensorineural hearing loss were excluded. Clinical, neurological and laboratory (seroconversion, read on for definition below, and blood viral load) test results as well as hearing status were used to determine risk factors. The researchers found that 416 and 617 (40.3 percent and 59.7 percent) of the 1,033 newborns included in the study were diagnosed with symptomatic cCMV infection and asymptomatic cCMV infection, respectively. Overall, 15.4 percent of the infants presented with congenital hearing loss, with half of those infants having no other symptoms.  

Using a regression model, the authors revealed three independent risk factors for cCMV: petechiae at birth, periventricular cysts on magnetic resonance imaging, and seroconversion in the first trimester. In immunology, seroconversion is the development of specific antibodies in the blood serum because of infection or immunization, including vaccination. During seroconversion, antigens enter the blood, and the immune system begins to produce antibodies in response.

Findings of this cross-sectional study suggest that newborns with cCMV infection and petechiae at birth, periventricular cysts on MRI, or a seroconversion in the first trimester had a higher risk of congenital hearing loss. The authors report that medical personnel may be able to use these risk factors to counsel parents in the prenatal and postnatal periods about the risk of congenital hearing loss. Linking clinical features to hearing loss also may provide new insights into the pathogenesis of cCMV-related hearing loss.

Read more about CMV in the January/February 2023 issue of Audiology Today.

References

Centers for Disease Control and Prevention (CDC). (2020) Congenital CMV and Hearing Loss. Cytomegalovirus (CMV) and Congenital CMV Infection (accessed January 4, 2023).

De Cuyper E, Acke F, Keymeulen A,  De Leenheer E, Van Hoecke H, Padalko E, et al. (2022) Risk factors for hearing loss at birth in newborns with congenital cytomegalovirus infection. JAMA Otolaryngol Head Neck Surg (accessed January 4, 2023).