Aims: Evaluate differences in perinatal and infectious risk factors in congenital unilateral (UHL) and bilateral (BHL) sensorineural hearing loss (SNHL), and their respective treatment outcomes. Methodology: Retrospective single-centre cohort study through Perth Children’s Hospital Newborn Hearing Screening clinic (March 2023–September 2025). Primary outcomes: age, sex, Aboriginality, location, gestation, family history (FMHx), congenital CMV, NICU admission, jaundice, ventilation/hypoxia, infection/sepsis, ototoxic medication use and genetic syndromes. Secondary outcomes: MRI findings, cochlear implantation (CI) and hearing aid uptake. Descriptive statistics were compared by laterality. Results: Of 153 infants with SNHL, 54% had BHL and 46% UHL. Males more commonly had BHL than UHL (60% vs 43%). Perinatal and infectious profiles were similar between BHL and UHL: Aboriginality 4% vs 6%, rurality 17% vs 16%, NICU 11% vs 9%, hypoxia/ventilation 8% vs 9%, infection/sepsis 7% vs 6%. Jaundice and congenital CMV were more frequent in UHL (19% vs 13%; 13% vs 7%), while FMHx, preterm birth, ototoxic medication use, and genetic syndromes were higher in BHL (22% vs 11%; 17% vs 9%; 10% vs 4%; 13% vs 9%). Abnormal MRI findings were more common in UHL (41% vs 22%) including cochlear nerve aplasia and hypoplasia (23% vs 5%, 9% vs 2%). Hearing-aid use and CI were more frequent in BHL (73% vs 47%; 20% vs 14%), while CI candidacy rejection was higher in UHL (27% vs 5%). Conclusion: UHL and BHL demonstrated similar perinatal and infectious profiles. UHL was associated with congenital CMV, jaundice and cochlear nerve anomalies, whereas BHL was linked to FMHx, preterm birth, ototoxic medication use, genetic syndromes and greater hearing aid use and likelihood of cochlear implantation. Our findings support targeted imaging and pathway planning by laterality. References: 1.https://pmc.ncbi.nlm.nih.gov/articles/PMC8313994/ 2.https://journals.sagepub.com/doi/full/10.1177/0145561319840578