Objectives: To assess the prevalence and characteristics of Autism Spectrum Disorder (ASD)-affected children attending autistic centers in 2 major cities in Saudi Arabia. Methods: A cross-sectional study, including ASD centers and schools (37 centers) in Makkah and Jeddah, Saudi Arabia was conducted between January and March 2020. Data were collected from records and parents of children with ASD using a questionnaire on sociodemographic, family history, consanguinity, severity, and maternal risk factors. Results: All centers in Makkah and Jeddah participated, with a total of 1,023 ASD children. The prevalence of ASD was 2.618 per 1,000 children for Jeddah, 3.68 per 1,000 children for Makkah and 2.81 per 1,000 children for both Jeddah and Makkah. There was no statistically significant relationship between the severity of ASD and sociodemographic, family and maternal risk factors. However, there was statistically significant relationship between severe ASD and ASD family history ( p =0.029, OR: 3.46 and 95% CI 1.14 to 10.5). Conclusions: The prevalence of ASD in Makkah and Jeddah was lower than the global prevalence of ASD. Individuals with a family history of ASD were more likely to have more severe ASD.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder linked to several genetic and environmental factors including antenatal stress. Hence, we aimed to examine whether a mother's stress during pregnancy is associated with the severity of autism spectrum disorder in children. The study was conducted with 459 mothers of children with autism (aged 2-14 years) who were attending rehabilitation and educational centers in the two major cities of Makkah and Jeddah in Saudi Arabia.Environmental factors, consanguinity, and ASD family history were assessed using a validated questionnaire. The Prenatal Life Events Scale questionnaire was used to assess whether the mothers were exposed to stress during pregnancy. Two models of ordinal regression analysis were conducted including gender, child age maternal age, parental age, maternal education, parental education, income nicotine exposure, mother taking medication during pregnancy, family history of ASD, gestation, consanguinity, exposure of prenatal life events (in model 1), and severity of prenatal life events (in model 2). Family history of ASD showed a statistically significant association with the severity of ASD in both regression models (p = .015, odds ratio [OR]: 4.261 in Model 1, and p = .014, OR: 4.901 in model 2). In model 2, the moderate severity prenatal life events showed higher statistically significant adjusted odds ratio for ASD severity compared to no stress (p = .031; OR: 3.82). Within the limitations of this study, prenatal stressors showed some potential contribution to ASD severity. Family history of ASD was the only factor that showed a persistent association with ASD severity. A study that assesses the effect of COVID-19 stress on ASD prevalence and severity is recommended.