B - 10 The Effect of Gestational Age on Development of Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder.

OBJECTIVE: Studies show individuals with comorbid neurodevelopmental disorders of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) have poorer emotional, behavioral, and cognitive outcomes. While preterm birth (< 37 weeks) is an identified risk factor for ASD and ADHD, it is important to consider gestational age (ga) as it relates to the development of comorbid ASD/ADHD (ASD/ADHD). The current study aims to understand the relationship between level of prematurity (LoP) and neurodevelopmental disorders.

METHOD: Participants included 10,711 children/adolescents (52.5% male) from the Environmental Influences on Child Health Outcomes (ECHO) Program. LoP was categorized as Extremely Preterm (36 weeks). Chi-square analysis was conducted to examine the relationship between LoP and neurodevelopmental disorder diagnoses as indicated in medical records. Logistic regression was also conducted to analyze the relationship between ga (weeks) and neurodevelopmental disorder diagnosis.

RESULTS: 1521 individuals were diagnosed with ASD (n = 537), ADHD (n = 778), or ASD/ADHD (n = 206); ga ranged from 22 to 43 weeks. Results indicated the relationship between LoP and diagnoses was significant, ꭓ2(9, 10,771) = 148.31, p < 0.001. Extremely Preterm individuals were more likely than Full-term individuals to have ASD, ADHD, or ASD/ADHD. It was found that the odds of having a neurodevelopmental disorder decreased by 5.8% per 1-week ga increase (95% CI[-0.069, -0.048]).

CONCLUSION: Results indicate gestational age is associated with greater risk of neurodevelopmental disorders, including comorbid ASD/ADHD. Improved understanding of the association between level of prematurity and comorbid ASD/ADHD diagnoses may help inform early intervention services enhancing children's outcomes throughout the lifespan.