Stroke in Pregnancy

Christina Mijalski Sells, MD, MPH; Steven K. Feske, MD


Semin Neurol. 2017;37(6):669-678. 

In This Article

Risk Factors for Stroke in Pregnancy

The common risk factors for stroke have a low prevalence in the generally young and healthy population of women of childbearing age. Kittner et al noted that women identified with pregnancy-associated strokes were on average 10 years younger and had a trend toward a decreased rate of hypertension, diabetes, ischemic stroke disease, and tobacco use when compared with women who had strokes unrelated to pregnancy.[2] Yet, these risk factors do contribute to pregnancy-associated stroke risk. Many of the studies discussed in the epidemiology section emphasized this effect of independent risk factors on the occurrence of pregnancy-associated stroke, most notably hypertension, diabetes, and tobacco use.[10–14] As noted above, the study by Kuklina et al suggested that a significant increase in the prevalence of hypertension and heart disease among women contributed to the increase in risk of pregnancy-related strokes between 1994 and 1995 and 2006 and 2007.[11] These findings suggest that these known vascular risk factors may predispose to stoke at any point during the pregnancy and the postpartum period. These same vascular risk factors were observed by Cheng et al in a Taiwanese population. In this population, the occurrence of stroke was significantly associated with hypertension, diabetes mellitus, coagulation disorders, migraine, obesity, cerebrovascular malformation, and parity of greater than three, suggesting that these common factors also contribute to risk in this population.[9] Underlying heart disease, cardiomyopathy, rheumatic or valvular heart disease, and heart failure also increase stroke risk.[12]

Other risk factors, including many cases of hypertension, are particular to pregnancy. Lanska and Kriscyo evaluated risk factors for peripartum stroke in an analysis of discharge data in United States hospitals from 1993 to 1994. The authors reported a significant association between peripartum stroke and hypertension, hemodynamic and electrolyte disorders, acid–base disorders, and cesarean delivery. Similarly, peripartum CVT was associated with hypertension, cesarean delivery, and infection.[12] In particular, hemodynamic, fluid balance, and coagulation abnormalities associated with the trauma and hemorrhage of child-birth, as well as the risk of infection after surgical procedures, contribute to the higher risk of stroke after delivery. Preeclampsia–eclampsia is a well-known independent risk factor for stroke, with a national incidence of 3 to 8%.[15,16] Brown et al found that preeclampsia increased the risk of ischemic stroke by 60%. Hypertension is an important independent risk factor for both ischemic and hemorrhagic stroke and is also a major criterion for the diagnosis of preeclampsia–eclampsia. As such, it has a complex relationship to the pathophysiology of stroke in pregnancy.

Although, pregnancy-related strokes are more common in older women, the proportion of strokes attributable to pregnancy is greater in women <35 years (18% of all strokes) compared with their older counterparts between the ages of 35 and 55 (1.4% of all strokes). This suggests that pregnancy-related strokes in older women are likely due in part to the accumulation of age-related vascular risk factors.[13]