OBJECTIVES/GOALS: Low-dose aspirin is an established treatment to prevent preeclampsia, a leading cause of maternal and perinatal complications. Nevertheless, aspirin failure is not uncommon. We are investigating whether a gain-of-function genetic polymorphism in a platelet thrombin receptor is associated with aspirin failure in the prevention of preeclampsia. METHODS/STUDY POPULATION: Women who had preeclampsia in an initial pregnancy who then received low-dose aspirin in a subsequent pregnancy will be evaluated. We will compare between women who developed preeclampsia despite aspirin (aspirin non-responders) to women who did not develop preeclampsia with aspirin treatment (aspirin responders). Specifically, we will evaluate the allelic frequency of a single nucleotide variant (rs773902) in PAR4 thrombin receptor on platelets. This variant is associated with increased platelet function and potentially aspirin resistance. In addition, we will analyze the platelet response to PAR4 activation before and 1 hour after administering a single 81 mg enteric-coated aspirin tablet. RESULTS/ANTICIPATED RESULTS: We hypothesize that the prevalence of the PAR4 variant will be significantly higher among women who had recurrence of preeclampsia despite aspirin therapy. We also postulate that women who developed preeclampsia despite aspirin prophylaxis and have the polymorphism will have increased platelet aggregation in response to activation of PAR4, either by thrombin or peptides that activate the receptor, both at baseline and 1 hour after aspirin administration. DISCUSSION/SIGNIFICANCE: If our hypothesis that aspirin failure in preeclampsia prevention is associated with the gain-of-function polymorphism in the platelet PAR4 thrombin receptor, there may be justification for additional experimental studies to assess whether better pregnancy outcomes can be obtained by targeting thrombin itself using low molecular weight heparin.