Kara Jo Swafford, MD
Stroke is the most common cause of long-term disability in women after pregnancy. In Canada, the incidence of stroke at delivery was 4.8 per 100,000 deliveries between 2003-2007, with an associated case fatality of 9.4%. In the United States, the rate of stroke during the antepartum period increased from 15 to 22 per 100,000 deliveries between 1994-1995 and 2006-2007, with the rate during the postpartum period increasing from 12 to 22 per 100,000 deliveries over the same time period.
Liu et al. investigated the incidence, trends and risk factors associated with stroke in pregnancy in Canada by performing a retrospective population-based cohort study including antenatal, delivery and postpartum admissions within 42 days between 2003-2016. Stroke incidence was 13.4 cases per 100,000 deliveries between 2003-2016; 60% hemorrhagic and 30% ischemic stroke, with a 7.4% case fatality rate. Over half (51.7%) of cases occurred during the postpartum period. The rate of stroke increased from 10.8 to 16.6 cases per 100,000 deliveries between 2003-2004 and 2015-2016. Risk increased with increasing gestational duration, advanced maternal age, gestational hypertension, preeclampsia, eclampsia, connective tissue disorders, sepsis, postpartum hemorrhage requiring blood transfusion, congenital heart disease, HIV infection and thrombophilia. Several potential confounders, such as smoking, body mass index, ethnicity and socio-economic status, were not available.
The authors suggest several potential reasons for the increase in pregnancy-associated stroke, including an increase in the prevalence of hypertension and the growing population of women with congenital heart disease who are surviving and becoming pregnant. Improvement in case ascertainment may also be a contributing factor.
A strong association between stroke in pregnancy and hypertension, combined with the high incidence of stroke during the postpartum period, highlight the importance of close follow-up for hypertensive women after delivery. Early recognition of women at greatest risk can prompt initiation of treatment to reduce stroke risk.
