Objective: The aims of this study were to evaluate the clinical characteristics of pregnant patients with Marfan syndrome and the maternal and fetal outcomes. Materials and Methods: Twelve pregnant women with Marfan syndrome were identified, who were treated in Beijing Anzhen Hospital Affiliated to Capital Medical University between January 2012 and May 2016. Results: Among 12 patients, six cases were diagnosed as type A aortic dissection, four cases were diagnosed as type B aortic dissection, one case had aortic dissection surgery before pregnancy, and one case was diagnosed with expansion of aortic sinus. Among the 12 cases, except for one patient with cardiac tamponade leading to heart failure, the remaining 11 cases had no complications. Six cases of newborns had a birth body mass between 1,080 to 3,500 grams; one case died after 14 days and five cases of newborns were alive without exception. Conclusion: Aortic dissection poses a serious risk for pregnant women with Marfan syndrome and the fetus, and the mortality rates for both the mother and the fetus are high. Early diagnosis and appropriate treatment should be based on maternal and fetal conditions. A multi-disciplinary team between obstetric and cardiovascular surgery is crucial in the outcome of these critical patients.