Impact of Preterm Birth Subtype on Risk of Diagnosis of Autism Spectrum Disorders in the Offspring

Preterm birth (PTB) can result from spontaneous preterm labor (spontaneous PTB, SPTB) or as an intervention by obstetricians where the baby is deliberately delivered preterm (Indicated PTB, IPTB) to get them to neonatal intensive care. The impact of these PTB subtypes on ASD risk is unclear. Therefore, we compared the risk of ASD diagnosis for children born from pregnancies that ended in SPTB or IPTB with those born at term. Electronic Health Record (EHR) data from women delivering singleton pregnancies between 2010 and 2021 were linked to their child's EHR data to create 337,868 maternal-child dyads. The impact of IPTB and SPTB on risk of ASD diagnosis in the child was evaluated by estimating adjusted hazards ratios (adj. HR) with 95% Confidence Intervals (CI). Both SPTB (adj. HR = 1.69; 95% CI:1.34, 2.12) and IPTB (adj. HR = 2.68; 95% CI: 1.98, 3.63) were significantly increased the risk of being diagnosed with ASD compared with term birth with a larger effect size for IPTB. This trend was observed for both boys and girls; late, as well as, early PTBs, and in all racial groups except non-hispanic Blacks where no association between IPTB or SPTB with ASD was detected. In conclusion, both IPTB and SPTB significantly increase the risk of ASD diagnosis in the offspring, however, the effect may be stronger for IPTB. This may reflect differences in the etiologies of the PTB subtypes. Lack of an association between either PTB subtype with ASD diagnosis in non-Hispanic Blacks suggests that race-ethnicity may be a risk modifier.