摘要:Background : Preeclampsia is one of the most common causes of maternal mortality. This complication has been attempted to prevent preeclampsia. Many drug treatments have also been tested, including aspirin, one of the drugs prescribed to prevent preeclampsia. Therefore, the present study was designed to summarize the findings and conclusions for the effect of aspirin on preeclampsia. Materials and Methods : In this systematic review, databases of Iran Doc, IRCT, SID, ProQuest, Medline, Scopus, and Cochrane were reviewed until October 2019. The keywords "Aspirin, Preeclampsia, hypertension, acetylsalicylic acid, ASA, Iran and clinical trials" were searched for references in the literature and their possible combinations in the title and abstract. Qualitative analysis of studies was performed according to the Evidence-Based Medicine Checklist for therapeutic studies. Results : Six clinical trials including 1,765 pregnant women were studied. In four studies, aspirin had a significant effect on the prevention of preeclampsia. In two studies, calcium-D had a significant effect on reducing the incidence of preeclampsia. Results regarding the effect of aspirin on infant birth weight, preterm labor and intrauterine growth restriction are inconsistent. Conclusion : The results showed that aspirin (within the lowest daily dose of 75mg) has a positive effect on the prevention of preeclampsia (pregnant women at risk of preeclampsia) among most of the studies and positive results. Judging the definitive efficacy of aspirin in relation to other variables such as neonatal birth weight, preterm labor and intrauterine growth restriction requires more and more detailed studies with a sufficient sample size.