Background <p>Preeclampsia (PE) is a major cause of maternal and fetal mortality andmorbidity. Its etiology is idiopathic, but it is known that the disease is associated with a prothrombotic state. In this context, the thrombin generation test (TGT) has been used to investigate hemostatic changes. This systematic review aimed to identify whether the pattern and magnitude of hemostatic changes observed by the TGT differ in PE pregnant women compared to those with normotensive blood pressure and healthy.</p> Methods <p>The databases used were PubMed, Lilacs, Web of Science and Embase. The observational studies included at least one TGT parameter. The risk of bias was evaluated using the Newcastle-Ottawa scale and Joanna Briggs Institute (JBI) Quality Appraisal Checklist.</p> Results <p>A total of 2,329 articles were retrieved, but only seven were included in the review totaling 850 participants: 290 with PE and 560 normotensive pregnant women. Most studies were considered to be of high quality. In the first trimesters, endogenous thrombin potential (ETP) and peak were significantly higher, while lagtime and time to peak were shorter in pregnant women with PE compared to normotensive women. However, pregnant women with severe PE presented lower ETP and peak, but longer lagtime compared to pregnant women with mild PE. Furthermore, in early onset PE, the activation of coagulation occurs earlier than in late-onset PE.</p> Conclusion <p>The presence of a state of hypercoagulability in PE is noteworthy, although attenuated in severe cases. According to our data, activation of the coagulation cascade occurs in the early stages of pregnancy, before the clinical manifestation of the disease, which provides an interesting and relevant clinical perspective for TGT.</p> Trial registration <p>Prospero (CRD42023477883).</p>