Universal Newborn Hearing Screening (UNHS) is a public health initiative designed to identify congenital hearing loss in infants shortly after birth. This practice is part of the larger Early Hearing Detection and Intervention (EHDI) program. The primary purpose of UNHS is to determine if a newborn requires further audiological assessment to confirm permanent hearing loss before leaving the hospital. UNHS is now the standard of care, ensuring virtually all newborns are screened regardless of risk factors.
The Need for Universal Screening
Before UNHS implementation, the average age for identifying permanent congenital hearing loss was typically between two and three years old. This significant delay meant children missed the most intensive period for language acquisition during their first few years of life. Hearing is fundamental for the development of speech, language, and cognition. Undetected hearing impairment can lead to severe and lifelong developmental delays.
The traditional approach involved targeted screening, focusing only on newborns with known risk factors like family history or a stay in the neonatal intensive care unit (NICU). However, this method missed approximately half of all infants born with hearing loss, as most of these children are born into families with no prior history of the condition. Recognizing that early intervention could substantially mitigate these negative outcomes provided the driving force for a shift toward universal screening for all newborns. Early identification and subsequent intervention can lead to language and speech development comparable to that of hearing peers.
Key Milestones in Implementation
The conversation about widespread screening began much earlier, with the 1965 Babbidge Report recommending the development of universally applied procedures for early identification. Formal pilot programs demonstrating the feasibility of mass newborn screening began in the late 1980s, primarily using the newly developed Otoacoustic Emissions (OAE) technology. A major turning point occurred in 1993, when the National Institutes of Health (NIH) Consensus Development Program formally recommended that all newborns be screened for hearing loss before hospital discharge.
Following the NIH recommendation, the Joint Committee on Infant Hearing (JCIH) endorsed the goal of universal detection in 1994, solidifying the standards for early hearing detection and intervention. Implementation accelerated on a state-by-state basis, often driven by legislative mandates. While fewer than 10% of newborns were screened in 1993, the adoption rate rose dramatically. By the early 2000s, nearly all states had laws or voluntary compliance programs in place. By 2020, over 97% of babies born in the United States were screened before one month of age.
How the Screening Works Today
The current standard of care involves a non-invasive screening, typically completed before the baby leaves the hospital. The procedure utilizes one or both of two objective testing methods to quickly assess the auditory system. One method is the Otoacoustic Emissions (OAE) test, which measures faint sounds produced by the inner ear’s outer hair cells in response to a clicking stimulus. A small probe is placed into the infant’s ear canal, and if the cochlea is functioning normally, it produces an echo that the probe records.
The second common method is the Automated Auditory Brainstem Response (AABR) test, which assesses the entire auditory pathway, including the hearing nerve and brainstem. Electrodes are placed on the baby’s head and neck to record the brain’s electrical activity in response to soft sounds delivered through earphones or probes. Both OAE and AABR are quick, often taking only a few minutes per ear, and are performed while the infant is quiet or asleep. The screening yields a simple “Pass” or “Refer” result; a “Refer” indicates only that the baby needs further testing, not a definitive diagnosis of permanent hearing loss.
The Follow-Up Process
If a newborn receives a “Refer” result on the initial screening, the result may be affected by vernix, fluid in the ear canal, or an unsettled baby. The next step is a re-screening, typically scheduled within a few weeks, or a direct referral for a comprehensive diagnostic audiological evaluation. This diagnostic testing must be performed by a specialist audiologist to determine the presence, type, and degree of any permanent hearing loss.
The entire process is guided by the Early Hearing Detection and Intervention (EHDI) program’s 1-3-6 timeline to ensure timely support. This benchmark recommends that screening be completed by one month of age, a definitive diagnosis be established by three months, and intervention services be started by six months of age. Intervention, such as hearing aids or enrollment in early educational programs, is most effective during the critical period of brain development in the first six months of life. National efforts focus on minimizing “loss to follow-up,” which occurs when an infant who refers on the screening does not receive the necessary diagnostic evaluation.