OBJECTIVE: Women with Marfan-related disorders face an elevated risk of aortic dissection during pregnancy and the postpartum period. This study aimed to investigate the incidence of aortic dissection during the perinatal period in women with Marfan-related disorders. METHODS: This retrospective cohort study analyzed data extracted from the Japanese Diagnosis Procedure Combination, a nationwide administrative claims database. We included women diagnosed with Marfan-related disorders (Marfan syndrome, Loeys-Dietz syndrome, or Ehlers-Danlos syndrome) who delivered between 2010 and 2023. We assessed the incidence of aortic dissection during pregnancy or postpartum hospitalization, and the incidence of re-hospitalization for aortic dissection. Moreover, we described the use of cabergoline and the incidence of aortic dissection. RESULTS: During the study period, we identified a total of 226 deliveries by 175 women with Marfan-related disorders. Cesarean section accounted for 69.0% of deliveries. During pregnancy, 1.8% of cases (4/226) experienced aortic dissection and required aortic surgery. In the postpartum period, 2.7% of cases (6/226) experienced aortic dissection during postpartum hospitalization. Within 1 year after delivery, 2.7% of cases (6/226) underwent re-hospitalization for aortic dissection. Cabergoline was administered for elective avoidance of breastfeeding within 2 days postpartum in 15 (6.6%) cases. The incidence of postpartum aortic dissection did not differ significantly between cabergoline users and non-users. CONCLUSIONS: Women with Marfan-related disorders may remain at risk of developing aortic dissection for up to 1 year postpartum.