Sex Differences in Autistic Youth Born Extremely Preterm

To evaluate sex differences in autistic traits in youth born extremely preterm (EP; 23–27 weeks) who were later diagnosed with autism spectrum disorder (ASD) at 10-years. A longitudinal cohort design from the Extremely Low Gestational Age Newborn Study (ELGAN) followed N = 857 EP infants from birth through 10-years. EP infants later diagnosed with ASD (N = 61, 20 females) participated in the study. Group differences were evaluated via inferential and Bayesian statistics (values > 1 suggest evidence for alternate hypothesis) on ASD screeners (M-CHAT at 2-years, SCQ and SRS-2 at 10-years), and gold-standard diagnostic measures (ADOS-2, ADI-R) at 10-years. Males scored significantly higher than females on measures of Social Affect from the ADOS-2, t(34.27)=-2.20, BF10 = 2.33, and measures of Repetitive and Restricted Behaviors from the ADI-R, t(40.52)=-2.85, BF10 = 5.26. Bayesian estimates suggested marginal evidence for sex differences in Nonverbal Communication, t(30.66)=-1.81, BF10 = 1.25, and Verbal Communication, t(24.64)=-1.89, BF10 = 1.39, from the ADI-R, wherein males scored higher than females. No statistically significant sex differences were identified on any of the ASD screeners at 2 (M-CHAT) or 10 years (SCQ). No significant sex differences were observed on any subscales of the SRS at 10 years. EP autistic males present with more autistic traits than EP autistic females on gold-standard diagnostic measures of autism at 10-years of age, despite not presenting with higher autistic traits on screeners at either age. These results align with sex differences observed in full-term, autistic youth. These results suggest ASD screeners may under identify autism in EP youth, particularly females.