No abstract

Autism Spectrum Disorder (ASD) combines a group of delays in neurocognitive development, which become more expressed before the age of three years old. Determining ASD characteristics in children for reliable diagnosis requires acknowledgement of the warning signs, which may manifest as restricted/repetitive patterns of behavior, interests in peculiar activities, and deficits in communication and social interaction. The aim of this study is to analyze and identify the most common warning signs in children with ASD in early childhood. A systematic review was conducted following PRISMA Statement directions with an online search in the following databases: SCOPUS, MEDLINE, Lilacs, Web of Science, ScienceDirect and SCIELO. The study motivation question used to guide the selected descriptors followed PICo strategy. The eligibility criteria considered full text articles published between 2017 and 2022, in Portuguese or English language. After applying the inclusion and exclusion criteria, 43 articles were included in the review and submitted to a full reading analysis and data extraction. Finally, the analysis of the results possibilities the understanding of the main warning signs of ASD  in children aged 0 to 6 years and with this it may help in the detection and possible early diagnosis by health professionals.