Women who experience a pregnancy-associated stroke are at an increased risk for long-term adverse health outcomes compared with pregnant women without a stroke, according to findings from a retrospective cohort study published in the journal Stroke.
Although pregnancy-related stroke is linked to high short-term morbidity and mortality, data on subsequent maternal outcomes are limited. Stroke is reported in approximately 30 per 100,000 pregnancies. Women with a pregnancy-associated stroke are at a higher risk for in-hospital mortality and longer length of hospitalization than pregnant women who do not experience a stroke.
Researchers sought to compare the long-term hazard of mortality and readmission to the hospital in patients who experience a stroke during pregnancy or in the puerperium period with 2 populations: young nonpregnant women with stroke and pregnant women without stroke. Women who survived the index admission were followed up until 2021.
Using the Canadian Institute for Health Information Discharge Abstract Database, between April 1, 2002, and December 31, 2020, they identified 3 cohorts of women aged 49 and younger in Ontario:
- Cohort 1. Patients who experienced a pregnancy-associated stroke, defined as “any hospitalization with a diagnosis of stroke during pregnancy, delivery, or up to 6 weeks postpartum.”
- Cohort 2. Patients admitted for an in-hospital livebirth, stillbirth, or intentional pregnancy termination on or after 20 completed weeks of gestation.
- Cohort 3: Young women who were not pregnant but hospitalized with a stroke diagnosis.
To identify stroke, the researchers used the validated case definitions of International Classification of Diseases 10th Canadian revision (ICD-10-CA) codes for ischemic stroke, intracerebral hemorrhage (ICH), or central venous sinus thrombosis.
A total of 1,496,473 pregnancies were identified. Among this population, 217 women were admitted for stroke (30.0% for ischemic stroke, 36.9% for ICH, and 33.2% for cerebral venous sinus thrombosis). Overall, 78.8% (171 of 217) of the strokes occurred during the third trimester or postpartum.
Characteristics of the patients and type of stroke differed between pregnant and nonpregnant women with stroke.
Compared with the 7604 nonpregnant women with stroke, the 217 pregnant women with stroke were much younger, more likely to have a hypertensive disorder of pregnancy, and more likely to experience a cerebral venous sinus thrombosis; however, they were less likely to experience chronic hypertension, dyslipidemia, or diabetes.
Pregnant women with stroke were less likely than nonpregnant women to be treated with intravenous thrombolysis (<5% of pregnant women vs 17.0% of nonpregnant patients) or endovascular thrombectomy (0% of pregnant women vs 12.0% of nonpregnant patients).
Among the 202 pregnant women with stroke who survived the index stroke admission, 41.6% (84 of 202) of them subsequently died or were readmitted during follow-up (6.8 events per 100 person-years). The median follow-up times were as follows: 5 years for women who experienced a pregnancy-associated stroke, 3 years for those with a nonpregnant-associated stroke, and 8 years for pregnant women without stroke.
At 1-year follow-up, pregnant women with stroke had a lower hazard of death and all-cause readmission compared with nonpregnant women with stroke (hazard ratio [HR], 0.64, 95% CI, 0.4-0.94), but this association was not observed during longer-term follow-up. In contrast, at the 1-year follow-up, pregnant women with stroke had a higher hazard for death and readmission compared with pregnant women without stroke (HR, 5.70; 95% CI, 3.04-10.66), with this relationship persisting for about a decade.
Several limitations of the study warrant mention. Due to the limitations associated with linked claims data, the researchers were unable to report on stroke severity, etiology, use of concurrent medications, and several vascular risk factors, including smoking; thus, residual confounding may exist. Additionally, the researchers did not have access to data on quality of life or functional status. Further, they were unable to identify those patients with stroke who were not admitted to the hospital, although this was most likely a rare situation, particularly among pregnant women.
The researchers concluded, “The observation that stroke during pregnancy is associated with long-term health consequences highlights the critical need for transitioning care postpartum to primary care or specialty neurology or internal medicine clinics to facilitate screening and treatment of vascular risk factors, educate and support healthy behaviors, and individualize care and treatment to the patient’s psychosocial context.”
Yu AYX, Nerenberg KA, Diong C, et al. Maternal health outcomes after pregnancy-associated stroke: a population-based study with 19 years of follow-up. Stroke. 2023. doi:10.1161/STROKEAHA.122.041471