A 29-year-old woman with Marfan syndrome, a bicuspid aortic valve, and a dilated aortic sinus (5.2 cm) presented herself in clinic 14 weeks pregnant. She was advised to discontinue the pregnancy due to risk of dissection; however, she decided to continue. She was treated with labetalol (300 mg/day) to reduce blood pressure and was admitted for bed rest from week 30. Her aortic diameter was assessed by echocardiography every 2nd week and remained unchanged. She was treated with betamethason at week 26 and the child was born by a caesarean section in week 35. The post-operative course was uneventful.