The rate of any type of pregnancy-related hospitalization for stroke in the United States increased from approximately 4,000 in 1994-1995 to about 6,000 in 2006-2007, based on data from a nationwide sample of more than 64 million pregnant women, according to findings published in the September issue of Stroke.
This 54% increase can be explained largely by postpartum hospitalizations in women with heart disease or hypertensive disorders, said Dr. Elena V. Kuklina and her associates at the Centers for Disease Control and Prevention in Atlanta.
The researchers compared ICD-9 code data from 1994 to 1995 with data from 2006 to 2007. Types of stroke included cerebral venous thrombosis, hemorrhagic, ischemic, subarachnoid, transient ischemic attack, and unspecified (Stroke 2011 July 28 [doi:10.1161/strokeaha.110.610592]).
Overall, hypertensive disorders were present in 11%, 23%, and 28% of prenatal, delivery, and postpartum hospitalizations, respectively, in 1994-1995, and these numbers increased to 17%, 29%, and 41% in 2006-2007. Only the increase in postpartum hospitalizations for stroke was statistically significant.
Heart disease was a complication in pregnancy-related hospitalizations for stroke in 16% of prenatal hospitalizations, 8% of delivery hospitalizations, and 9% of postpartum hospitalizations in 1994-1995, whereas that was the case in 16%, 8%, and 12% of the hospitalizations, respectively, in 2006-2007.
The rate of any stroke per 1,000 deliveries increased significantly for prenatal hospitalizations and postpartum hospitalizations between the two time periods (from 0.15 to 0.22 and from 0.12 to 0.22, respectively). However, the rate of any stroke during delivery hospitalizations remained unchanged at 0.27.
After adjusting for confounding variables, patients who were hospitalized with hypertensive disorders during pregnancy, during delivery, and post partum were 1.8, 5.6, and 3.5 times more likely, respectively, to have indications of stroke, compared with patients without hypertensive disorders, the researchers noted.
In addition, patients who were hospitalized with heart disease during the prenatal period and the delivery period were, respectively, 9.4 times as likely and 5.4 times as likely to have indications of stroke.
The current recommendations from the American Heart Association and the American Stroke Association for managing pregnant women with a history of noncardioembolic stroke or at risk of cardioembolic stroke include treatment with anticoagulant therapy in the form of unfractionated heparin or low-molecular-weight heparin until week 13, followed by low dose aspirin for the rest of the pregnancy (Stroke 2011;42:227-76).
The findings support data from previous studies at single institutions, although they were limited by the use of ICD-9 codes that were not validated by a review of medical records, the researchers noted.
However, the findings suggest that cardiovascular disease surveillance of pregnant women remains essential to improving both the design of future studies and the clinical care of pregnant women, Dr. Kuklina and her associates added.
Dr. Kuklina and her associates said they had no relevant financial disclosures.