A randomized clinical trial to assess the efficiency of acetylsalicylic acid (aspirin) 150 mg/day started before 20 weeks of gestation in the prevention on maternal and fœtal complications in pregnant women with chronic hypertension.
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
---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,