There is an increase in the risk of stroke during pregnancy (thirteen-fold relative risk) but the risk is greatest in the postpartum period. Risk factors for venous thromboembolic disease, during pregnancy and post-partum, can be identified in as many as 75% of pregnant women. Both arterial and venous stroke are associated with pregnancy. Hypertension and preeclampsia have long been recognized as risk factors. Hormonal, coagulation and volume (including dehydration) changes may contribute to stroke in the postpartum period.
The relative risk of cerebral hemorrhage is 2.5 during pregnancy with a marked increase to 28.3 in the postpartum period. Multiple etiologies include aneurismal rupture, arteriovenous malformation and other vascular malformation, vasculitis, coagulopathy such as disseminated intravascular coagulapoathy and preeclampsia. While hemorrhages secondary to aneurysm tend to occur during each trimester, there are multiple reports of the hemorrhage associated with arteriovenous malformation occurring in the second trimester. Mortality associated with cerebral hemorrhage during pregnancy is greater than mortality associated with cerebral infarction. Reports of mortality range from 27-40 %.
Antovic et al found that a procoagulant state perseveres in patients with a history of pregnancy-related deep vein thrombosis, even when the symptomatic phase is over. The mechanisms behind such an imbalance in overall hemostasis are enhanced thrombin generation and depressed fibrinolysis. These results may underscore the need for thromboprophylaxis to prevent recurrence of thromboembolism in risk situations.
3. Antovic A, Blomback M, Bremme K, Van Rooijen M, He S, Increased hemostasis potential persists in women with previous thromboembolism with or without APC resistance, Journal of Thrombosis & Haemostasis. 1(12):2531-5, 2003