Background <p>Recommendations for the preventive management of pre-eclampsia remain inconsistent across existing guidelines, which may adversely affect clinical decision-making. It is crucial to summarize and compare the existing guidelines to identify inconsistencies and guide future research.</p> Methods <p>We conducted a systematic review and quality assessment of clinical guidelines for the preventive management of pre-eclampsia. Six literature databases and 19 guideline databases or official websites were searched from their inception to May 31, 2024. Two reviewers initially screened the retrieved articles. Data extraction was performed by one reviewer and verified by another. Five reviewers appraised the quality using the AGREE II instrument. Basic characteristics of the guidelines were described as frequency and proportion. A qualitative analysis was performed to compare inconsistencies in the recommendations. The intraclass correlation coefficient (ICC) was calculated to evaluate the consistency of item scores in the AGREE II tool among reviewers. The standardized domain scores for all guidelines were expressed as median and interquartile range (IQR). The Heat maps and Sankey diagrams were generated to visualize variations.</p> Results <p>A total of 32 guidelines published between 2004 and 2024 were included. Recommendations for risk factors exhibited marked variations, with only 8 (27%) guidelines integrating all three categories (maternal, biochemical, imaging-defined). Most guidelines (12 of 14) recommended qualitative methods to classify patients into low-, moderate-, or high-risk categories. The Fetal Medicine Foundation (FMF) algorithm was the only quantitative model endorsed for prediction. Aspirin was universally recommended for high-risk women, but with wide variations in dose and timing. The highest recommended dose was more than three times the lowest dose. The most frequently recommended initiation time was before 16 weeks’ gestation, with cessation at 36 weeks’ gestation the most common. Guideline quality was generally high (87.5% rated excellent overall), but the “Rigour of Development” domain scored lowest (median 43.8%), revealing key methodological shortcomings in updating procedures.</p> Conclusions <p>Substantial inconsistencies persist in recommendations for the preventive management of pre-eclampsia across existing guidelines, highlighting the need for further research. Moreover, the methodological rigor of guideline development requires enhancement to ensure more reliable clinical advice.</p> Trial registration <p>ID CRD42024557782</p>