A host of factors, some of them preventable or treatable, increase the risk of pregnancy-related stroke among women hospitalized for preeclampsia, according to findings from a case-control study of nearly 800 preeclamptic women in New York.
Women who experienced a stroke were roughly seven times more likely to have severe preeclampsia or eclampsia, and about three to four times more likely to have an infection, a prothrombotic state, a coagulopathy, or chronic hypertension, according to the findings (Stroke. 2017 May 25.).
“Prospective studies are needed to confirm these findings and develop interventions aimed at preventing strokes in this uniquely vulnerable group,” they added.
For the study, the investigators used billing data from the 2003-2012 New York State Department of Health inpatient database to identify women aged 12-55 years admitted with preeclampsia.
They matched each woman who experienced pregnancy-associated stroke with three randomly selected controls of the same age, race/ethnicity, and insurance status. They then compared the groups on a set of predefined risk factors.
Results showed that of 88,857 women admitted for preeclampsia during the study period, 0.2% experienced pregnancy-associated stroke, translating to a cumulative incidence of 222 per 100,000 preeclamptic women, a value more than six times that seen in the general pregnant population, the investigators noted.
The majority of strokes occurred post partum (66.5%), but more than a quarter occurred before delivery (27.9%). The single most common type of stroke was hemorrhagic (46.7%).
The 197 women with preeclampsia who experienced pregnancy-associated stroke had a sharply higher rate of in-hospital mortality (13.2%), compared with the 591 controls (0.2%).
In multivariate analysis, women with preeclampsia experiencing stroke were more likely to have severe preeclampsia or eclampsia (odds ratio, 7.2; 95% confidence interval, 4.6-11.3), or infections at the time of admission (OR, 3.0; 95% CI, 1.6-5.8), predominantly genitourinary infections.
Other risk factors for pregnancy-associated stroke included prothrombotic states (OR, 3.5; 95% CI, 1.3-9.2), coagulopathies (OR, 3.1; 95% CI, 1.3-7.1), or chronic hypertension (OR, 3.2; 95% CI, 1.8-5.5).
The findings were similar when women were matched by the severity of preeclampsia, when women with eclampsia were excluded, or when women with only postpartum stroke were included.
Heart disease, multiple gestation, and previous pregnancies were not significantly independently associated with the risk of pregnancy-associated stroke.
“The ethnic and regional diversity of New York State increases the generalizability of our findings,” the investigators wrote. “Matching of cases and controls allowed for nuanced analysis of other risk factors.”
But the study may have missed some cases of preeclampsia not formally diagnosed, and the timing of infections relative to stroke was unknown, they acknowledged. Additionally, they noted that causality cannot be inferred from the observational study, and therefore the results should be interpreted cautiously.
The investigators reported research support from the National Institutes of Health. They had no other financial disclosures.