Stroke During Pregnancy May Be on the Rise in US

January 16, 2020

The incidence of acute stroke or transient ischemic attack (TIA) during pregnancy and the post-partum period in the United States may be increasing, a new study suggests.

The study analyzed information from the Nationwide Inpatient Sample, the largest publicly available all-payer database containing discharge-level administrative data on inpatient diagnoses and procedures from a stratified sample of approximately 20% of US hospitals.

Results showed that acute stroke occurred in 1 of every 2222 pregnancy-related hospitalization, and these rates did not decrease over the 9-year study period — from 2007 to 2015.

"We found an incidence of stroke in pregnancy of about 0.5%, with not much change over the time period studied, although a sensitivity analysis excluding unspecified stroke or TIA showed an increasing trend for acute ischemic stroke and hemorrhagic stroke," lead author Islam Elgendy, MD, Massachusetts General Hospital, Boston, told Medscape Medical News.

The study was published online January 13 in the Journal of the American College of Cardiology.

In an accompanying editorial, Ralph Sacco, MD, and Nicole Sur, MD, both at the University of Miami Miller School of Medicine, say these new data suggest that stroke-specific coding has improved over time, and the incidence of true stroke in pregnancy may be on the rise in the United States.

The study also showed that among patients who had a stroke during pregnancy, risk factors increased over the study period.

"We are not doing a good job in preventing or identifying patents at high-risk of stroke," Elgendy said. "These include patients with hyperlipidemia, obesity, smoking, gestational hypertension, and those with a previous history of stroke. Traditional cardiovascular risk factors are increasing in the younger population — our results are a reflection of this," he added.

Based on these data, more needs to be done to better identify women at high risk of stroke during pregnancy, he said. "We need to be more vigilant in identifying and treating traditional cardiovascular risk factors in early pregnancy, and we need to refer high-risk patients to the cardio-obstetric teams to help manage the pregnancy and help reduce risk," Elgendy noted.

Other evidence suggests that pre-eclampsia and eclampsia are not being adequately prevented or treated, and rates of these conditions are increasing in the United States, which will also contribute to increased stroke rates in pregnancy, he said.

Results of the study showed that among 37,360,772 hospitalizations for pregnancy and puerperium from January 2007 through September 2015, 16,694 (0.045%) involved acute stroke/TIA. Of these, 47.2% were ischemic stroke/TIA, 31.0% were hemorrhagic stroke, and 3652 (21.8%) involved unspecified stroke.

Compared with those who did not have acute stroke/TIA, those with acute stroke/TIA were older (with a steep increase for women aged over 45 years); were more likely to be black, obese, and smokers; and had a higher proportion of hypertension, diabetes, hyperlipidemia, atrial fibrillation, coronary artery disease, atrial septal defect, migraine, and rheumatologic diseases. Pregnant women with acute stroke/TIA also had a higher proportion of pre-eclampsia/eclampsia.

The researchers found a high maternal mortality rate with acute stroke/TIA at approximately 4.2%. While hospital mortality after a stroke decreased during the study period from 5.5% in 2007 to 2.7% in 2015, women having a stroke during pregnancy still had a 400-times increased risk of death compared with women who did not.

As well as doing more to identity women at risk of stroke during pregnancy, Elgendy stressed that further research is needed on how to treat it when it co-occurs.

"Pregnant women are generally excluded from clinical trials of new treatments," he said. "Guidelines do not recommend withholding thrombolysis, but there is very little data on safety, and this is particularly problematic in the early post-partum period where there is high risk of hemorrhage."

Risk Factors Largely Preventable

In their editorial, Sacco and Sur point out that the major risk factors associated with pregnancy-related stroke are largely preventable. "Public health interventions targeting preventive measures in younger populations are key to reducing the prevalence of vascular risk factors and stroke in this segment of the population," they say.

Sacco and Sur call for the implementation of appropriate counseling, monitoring, and more aggressive treatment and preventive measures for higher risk women including those of older age, those with hypertensive disorders of pregnancy, heart disease, or conventional vascular risk factors, as well as black and Asian women.

They also note that nontraditional risk factors such as migraine and depression were independently associated with stroke/TIA in pregnancy in the present study, which raises questions about other underlying mechanisms of stroke in pregnancy that require further study.

The study authors have disclosed no relevant financial relationships.

J Am Coll Cardiol. Published online January 13, 2019. Abstract, Editorial

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