Abstract 4373112: High-dose Aspirin is more effective than Low-dose Aspirin for Prevention of Preeclampsia in High-risk Pregnant Women: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Introduction: Preeclampsia is a multisystem progressive disease of pregnancy, characterized by a new onset of hypertension (≥ 140/90 mm Hg) with proteinuria after the 20th week of gestation. There is a conflict between United States guidelines that recommend Low-dose aspirin (LDA) and United Kingdom guidelines that recommend High-dose aspirin (HDA) for the prevention of preeclampsia in high-risk pregnant women. After the latest study that recommends HDA and the absence of pairwise meta-analyses comparing two doses, we aimed to conduct a comprehensive pairwise meta-analysis to assess whether HDA is better than LDA in the prevention of preeclampsia. Methods: We conducted a systematic search on PubMed, Scopus, Cochrane Central, and Web of Science (WOS) from inception until June 2025. All randomized controlled trials (RCTs) comparing LDA and HDA in high-risk pregnant women were included. Our primary outcome was the incidence of preeclampsia (PE), while secondary outcomes were Placental abruption, Pre-term delivery, and Intrauterine Growth Restriction (IUGR). Using random-effects models, we calculated risk ratios (RR) with 95% confidence intervals (CIs). Results: A total of 8 RCTs with 1,290 patients from the United States, Canada, England, and different Asian countries were included, among whom 642 (49.8%) patients were randomized to HDA. All studies compared HDA (≥ 150 mg) and LDA (75 mg to 81 mg). Patients with LDA had a higher risk of Preeclampsia (RR: 1.71, 95% CI: 1.19 to 2.44, p<0.001) compared to HDA. There was no significant difference between the LDA and HDA regarding Placental abruption, Pre-term delivery, and IUGR. With a pooled RR with a 95% CI (1.8, [0.91 to 3.54], P = 0.09), (1.25, [0.79 to 1.97], P = 0.34), (1.5, [0.93 to 2.42], P = 0.1), respectively. Conclusion: Among high-risk pregnant women, LDA was associated with a 71% higher incidence of preeclampsia than HDA. These results support the use of HDA as a preventive medication for preeclampsia in high-risk pregnant women.