Congenital anomalies identified during early childhood in NICU infants with bilateral hearing loss: a multi-centre longitudinal cohort study.

Introduction: Infants requiring neonatal intensive care are exposed to a range of biological insults during critical periods of brain development, increasing the risk of both bilateral hearing loss (BHL) and neurodevelopmental impairment (NDI). While hearing loss is often seen as a sensory deficit, emerging evidence suggests it may reflect broader disturbances in neurodevelopment. The extent to which multisystem abnormalities associated with BHL are documented at birth or identified during early childhood follow-up remains unclear. This study investigated the temporal relationship between congenital anomalies, hearing loss, and neurodevelopmental outcomes in NICU populations. Methods: A retrospective multi-centre cohort study was conducted across two UK tertiary NICUs. Infants with confirmed permanent BHL were matched to NICU controls without hearing loss based on gestational age, birthweight and sex. Congenital anomalies were assessed at birth and at 2-years using standardised clinical classifications. Neurodevelopmental outcomes at 2-years were categorised as normal-mild or moderate-severe delay. Stratified analyses by site were performed, with pooled associations estimated using Mantel-Haenszel methods. Multivariable logistic regression was used to examine independent predictors of NDI. Results: At birth, results indicate there was no significant difference in congenital anomaly prevalence between infants with BHL and matched controls (Mantel-Haenszel χ Discussion: These findings suggest that BHL in NICU populations may be associated with broader developmental vulnerability rather than isolated auditory pathology. Longitudinal follow-up may therefore be important for identifying congenital anomalies that are not clinically apparent or documented in the neonatal period and informing more targeted developmental surveillance.