The Association between Threatened Abortion and the Risk of Autism Spectrum Disorders among Children: A Meta-Analysis

BACKGROUND: The current study is aimed at updating the observational studies on the relationship between threatened abortion and the risk of ASD. METHODS: The search keywords were covered in three electronic databases PubMed, Web of Science, and Scopus up to April 2022. The modified Newcastle–Ottawa scale (NOS) was applied to detect the quality of epidemiological studies. We used the chi-square test and the I(2) statistic to show the heterogeneity among articles. I(2) more than 50% was considered high heterogeneity. Egger's and Begg's line regression tests were used for evaluating the publication bias. The random-effects model was applied for the analysis of the findings. The Stata 13.0 software package was applied for analysis and indicated p value less than 0.05 as a significant level. RESULTS: The pooled analysis reported significant differences between threatened abortion and the risk of ASD in adjusted studies (OR = 1.93; 95% CI: 1.12, 2.73; I(2) = 59.5.0%) and in crude studies (OR = 2.17; 95% CI: 1.46, 2.88; I(2) = 39.5%). The evidence of publication bias was not found. CONCLUSIONS: The findings suggest that threatened abortion is a risk factor for ASD. As a result, screening tools to detect are necessary in mothers facing a threatened abortion.