We intend to conduct a randomized controlled interventional study among individuals attending a peripherally located government-run tertiary care hospital, to see whether the use of a higher 150 mg dose of aspirin, compared with that of 75 mg aspirin, in women at risk of pre-eclampsia, has greater benefit in terms of certain maternal and perinatal outcomes. The present study primarily aims to compare differences in the efficacy and safety of prophylactic use of 150 mg aspirin in comparison to 75 mg aspirin in women with known risk factors for development of preeclampsia. A two-arm double-blind parallel group randomized control trial will be conducted in the Department of Obstetrics and Gynaecology, Rampurhat Govt Medical College, Birbhum. Pregnant women between 12 and 14 weeks of gestational age attending the antenatal clinic and meeting the inclusion criteria will be enrolled in the study after obtaining a written informed consent. The study will be carried out over a period of 1.5 years with a target sample size of 1518 . Exclusion criteria include active peptic ulcer disease, bleeding disorder, thrombocytopenia , history of vaginal bleeding and fetus diagnosed with malformations or aneuploidy during ultrasound screening, known allergy to aspirin.