Pediatric hearing loss in the universal newborn hearing screening era: etiologies, risk indicators, and clinical phenotypes.

Childhood hearing loss poses significant developmental and public health challenges, impacting language acquisition, cognitive development, social participation, and educational outcomes. Universal newborn hearing screening (UNHS) has notably enhanced the early identification of congenital hearing loss, yet limitations persist. Mild, unilateral, delayed-onset, progressive, and certain neural forms of hearing loss may remain undetected during a single neonatal screening session. This review consolidates current evidence regarding the etiologies, risk indicators, and clinical features of pediatric hearing loss in the context of UNHS. Essential areas of focus encompass genetic causes and pharmacogenetic susceptibility, congenital cytomegalovirus infection, intrauterine nutritional and metabolic conditions, environmental and lifestyle exposures, alongside perinatal or neonatal intensive care unit-related risks such as prematurity, hyperbilirubinemia, hypoxia, infection, and exposure to ototoxic medications. These factors exhibit varied clinical implications: some serve as direct causes of hearing loss, while others signify heightened vulnerability to delayed-onset or progressive auditory dysfunction. The evidence highlights a developmental perspective on pediatric hearing loss, indicating that auditory risks may emerge postnatally and cannot be ruled out based solely on normal newborn screening results. Distinguishing between etiology, risk indicators, and clinical phenotype may enhance the identification of children requiring intensified post-screening monitoring. Future research should aim to refine causal evidence, genotype-phenotype correlations, and viable strategies for risk-based follow-up.