72 Identifying Perinatal and Neonatal Factors Associated with Autism Spectrum Disorder among Preterm Infants Born < 29 Weeks’ Gestation

Abstract Primary Subject area Neonatal-Perinatal Medicine Background Preterm infants born <29 weeks’ gestational age (GA) are at risk for autism spectrum disorder (ASD), typically diagnosed at age >2 years. Perinatal and neonatal factors, including interventions and morbidities during neonatal intensive care unit admission, may contribute to the risk of ASD among these infants. Objectives We aimed to assess the incidence of and risk factors for, ASD among preterm infants born < 29 weeks’ GA. Design/Methods <29 weeks’ GA admitted 2009-2017 to two tertiary NICUs and followed ≥18 months at the Neonatal Follow-Up Clinic. Primary outcome was ASD defined as a confirmed diagnosis using standardized testing or suspected diagnosis at >18 months of corrected age. Patient data and 18-month developmental outcomes were obtained from the local Canadian Neonatal Follow Up Network database and from chart review. Stepwise logistic regression was used to identify significant perinatal, neonatal, and socio-economic factors associated with ASD. Results Among 300 eligible infants, 47 (15.7%) developed ASD (Figure 1, Table 1). Mean follow-up duration was 3.9 ± 1.4 years and mean age at diagnosis was 3.7 ± 1.5 years. Male sex (adjusted odds ratio [aOR] 4.63, 95% CI 2.12, 10.10), small for gestational age status (aOR 3.03, 95% CI 1.02, 9.01), maternal age ≥ 35 years at delivery (aOR 2.22, 95% CI 1.08, 4.57), and tobacco use in utero (aOR 5.67, 95% CI 1.86, 17.29) were significantly associated with ASD. Major neonatal morbidities (retinopathy of prematurity, bronchopulmonary dysplasia, necrotizing enterocolitis, late-onset sepsis, severe neurological injury) were not associated with ASD. Among infants with a complete 18-month corrected age developmental assessment and later diagnosed with ASD, 46% (19/41) did not have significant neurodevelopment impairment (Bayley-III < 70, deafness, blindness, or cerebral palsy). Conclusion ASD is a significant morbidity among infants born < 29 weeks’ GA. ASD was associated with infant and prenatal risk factors but not with neonatal morbidities or socio-economic factors. These findings emphasize the need for ASD evaluation among preterm infants < 29 weeks and for reporting developmental outcomes beyond 18-months corrected age.