Newly released guidelines provide the first evidence-based recommendations for preventing stroke in women.
The document addresses the issues that uniquely increase stroke risk in women – pregnancy, hormonal therapy, contraception, and migraine – along with factors like atrial fibrillation and obesity, Dr. Cheryl Bushnell and her colleagues wrote in the February issue of Stroke.
"If you are a woman, you share many of the same risk factors for stroke with men, but your risk is also influenced by hormones, reproductive health, pregnancy, childbirth, and other sex-related factors," Dr. Bushnell noted in a press statement.
The document – created by the American Heart Association and American Stroke Association – is the first to look at these gender-specific issues, wrote Dr. Bushnell, director of the Stroke Center at Wake Forest Baptist Medical Center in Winston-Salem, N.C. (Stroke 2014 [doi:10.1161/01.str.0000442009.06663.48]).
It provides graded evidence for preventive strategies in a number of risk categories. Evidence was obtained by examining dozens of studies numbering hundreds of thousands of women. But despite the extant literature, Dr. Bushnell and her colleagues said more research needs to be conducted.
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Few studies have examined the link between migraine with aura and stroke, although current data suggests that the risk may be doubled overall.
"There is a need for recognition of women’s unique, sex-specific stroke risk factors, and a risk score that includes these factors would thereby identify women at risk," they wrote. "Similarly, it is important to improve stroke awareness and provide more rigorous education to women at younger ages, including childbearing ages."
The guidelines are aimed at primary care providers, who have the biggest interface with women at a prevention level – and intended to help them forge an active partnership with patients.
"More importantly," the authors wrote, "this guideline may empower women and their families to understand their own risk and how they can minimize the chances of having a stroke."
Pregnancy
For recommendations on pregnancy outcomes and stroke related to preeclampsia, the guidelines drew on evidence from 17 studies.
For women with chronic primary or secondary hypertension, or with a history of pregnancy-related hypertension, Level A evidence supports using low-dose aspirin during the second and third trimester. Level A evidence also supports calcium supplementation to prevent preeclampsia in women with low dietary intake.
There was also a Level A recommendation to treat severe hypertension during pregnancy with safe antihypertensives (methyldopa, labetalol, and nifedipine). Level B evidence supported treating moderate hypertension. The use of atenolol, angiotensin receptor blockers, and direct renin inhibitors is contraindicated because of teratogenicity.
Because preeclampsia increases lifelong stroke risk, the guidelines also recommended evaluating these women within 1 year of giving birth, and, based on their individual and family risk factors, possibly treating them for cardiovascular risk factors.
Oral contraceptives
Four studies comprising about 800,000 women examined the risk of stroke in women using hormonal birth control.
Level A evidence did not support routine screening for prothrombotic mutations before starting oral contraception. But there was Level B evidence that oral contraceptives may be harmful in women who had risk factors, including cigarette use and prior thromboembolic events.
Menopause-related hormone therapy
Seven studies – including the Women’s Health Initiative – examined the links between stroke and hormone therapy in about 37,000 women. Two recommendations supported by Level A evidence were made.
Hormone therapy should not be used for either primary or secondary stroke prevention in postmenopausal women.
Selective estrogen receptor modulators (raloxifene, tamoxifen, and tibolone) should not be used for primary prevention of stroke.
Migraine with aura
There is scant literature examining the link between migraine with aura and stroke, although what does exist suggests that the risk may be doubled overall. The addition of another factor, like pregnancy or preeclampsia, dramatically increases the risk. But because these data are low in number, the recommendations are the same as they are for men.
Level B evidence supports smoking cessation in women with migraine and aura. Level C evidence suggests that treatments that reduce the frequency of migraine may also reduce the risk of stroke.
Obesity and metabolic syndrome
A healthy lifestyle of eating whole foods, exercise, and abstaining from tobacco has been shown to lower stroke incidence in both women and men. But subgroup analyses hint that men derive the most benefit. Women-only studies of these interventions have posted mixed results about their ability to reduce stroke in women.
The authors said much more research is necessary to target interventions that are especially beneficial for women. Until then, Level B evidence supports maintaining a lifestyle of exercise, healthy eating, no tobacco use, and moderate alcohol intake (a drink a day or less) for women who aren’t pregnant.