You have just had a conversation about the risk factors associated with developing pre-eclampsia with a 28-year-old female in your GP surgery. She has two or more of the moderate risk factors required to develop pre-eclampsia including a family history and a first pregnancy. You referred her to consultant-led care at the nearest hospital however the hospital is short-staffed and she cannot be seen by the hospital until after 12 weeks of pregnancy – she is currently 6 weeks pregnant. What is the most appropriate drug to start from 12 weeks gestation to continue to birth?