Chronic Hypertension and Acetyl Salicylic Acid in Pregnancy

Inclusion Criteria: * Pregnant patient between 10 and 19 weeks of gestation + 6 days * Chronic hypertension, whether treated or not, know before pregnancy or diagnosed before randomization * Singleton pregnancy * Signed the written informed consent * Affiliation to social security Exclusion Criteria: * ---Medical history requiring anticoagulation (antiphospholipid syndrome, deep vein thromboembolic disease, pulmonary embolism, atherothrombosis, patient with mechanical heart valves), * Patient receiving aspirin for another indication outside pregnancy, * Patient with significant proteinuria (\> 300mg/24 hours or a proteinuria/creatininuria ratio ≥ 30mg/mmol), * Active bleeding, * History of severe PE with delivery \< 34 weeks of gestation, * Hypersensitivity to salicylates such as aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), * Platelet count lower than 100,000 cells/microliter (dosage less than 6 months old), * Hemostasis disorders, including hemophilia (with thrombocytopenia) * Any constitutional or acquired hemorrhagic disease, (including digestive hemorrhages, history of hemorrhagic stroke and thrombocytopenia * Human immunodeficiency virus, or hepatitis B virus, or hepatitis C virus positive serum, * Patient included in another interventional study which could interfere with the results of the study, * Age \<18 years old, * Women under the protection of justice, * Patients with psychiatric follow-up, poor understanding of French or cognitive problems, * Duodenal ulcer, * Severe renal impairment, * Severe hepatic insufficiency, * Severe cardiac impairment, * Gout, * Patients with known glucose-6-phosphate dehydrogenase deficiency,