Abstract
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.