The association between preterm delivery and autism spectrum disorder in childhood: A retrospective cohort study

Background: Prematurity complications are a leading cause of mortality and morbidity in offspring, including adverse neurodevelopmental outcomes. The association between preterm birth (PTB) and autism spectrum disorder (ASD) remains debated. Objective: To investigate the association between PTB and ASD diagnosis during childhood. Methods: This cohort study analyzed data from community clinics and a tertiary hospital, encompassing deliveries from 2005 to 2017. ASD incidence was compared across gestational age categories: extremely preterm (<28 weeks), very preterm (28-32 weeks), moderate to late preterm (32-37 weeks), and term (>= 37 weeks). Additional comparisons were made between all preterm (<37 weeks) and term deliveries (>= 37 weeks). Cumulative ASD incidence was assessed using Kaplan-Meier survival curves and a Cox proportional hazards model adjusted for potential confounders. Results: Among 114 975 pregnancies, 0.3% delivered at <28 weeks, 0.6% at 28-32 weeks, and 6% at 32-37 weeks, with 6.9% preterm deliveries overall. Univariable analysis revealed a significant association between PTB and ASD (1.6% for <28 weeks vs 0.3% for 28-32 weeks vs 0.8% for 32-37 weeks vs 0.7% for term, P = 0.036). Crude ASD incidence was 0.8% (odds ratio [OR] 1.21, 95% confidence interval [CI] 0.93-1.56, P = 0.15). However, adjusted results showed no significant association: adjusted hazard ratio = 0.74 (95% CI 0.24-2.34, P = 0.61) for <28 weeks, 0.99 (95% CI 0.24-3.99, P = 0.98) for 28-32 weeks, and 1.07 (95% CI 0.81-1.43, P = 0.63) for 32-37 weeks. Kaplan-Meier analysis showed similar cumulative ASD incidence across groups (P = 0.855). Conclusion: This retrospective cohort study found no significant association between PTB and childhood ASD diagnosis.