What is aspirin?
Aspirin is an antiplatelet medication. Antiplatelets make the blood less sticky, which helps prevent blood clots from forming.
Can aspirin help during a heart attack?
Studies show that taking aspirin during a heart attack reduces the risk of dying by 23%.11 A chewed aspirin (162-325 mg) helps prevent further clots developing. Research shows that women having a heart attack are just as likely to benefit from aspirin as men.12
Can aspirin prevent another heart attack in women who've already had one?
Women who have already had a heart attack, stroke, or undergone angioplasty or bypass surgery should take daily aspirin (75-325 mg).7, 13 Aspirin reduces the chances of further heart problems by 25%.14 Although aspirin sometimes works as a painkiller, it does not reduce chest pain ( angina). It does reduce the risk of dying for people who suffer from angina.15 One small study suggested that aspirin may not be as effective in women with angina compared with men. The women taking aspirin were more likely to suffer episodes of chest pain than men.16
If I'm at risk for heart disease, should I take aspirin?
What about women who have not had a heart attack or stroke — should they take a daily aspirin? The most recent guidelines for the prevention of cardiovascular disease in women recommend daily aspirin (75-162 mg) for women at high-risk for coronary artery disease.17 High risk is defined as a greater than 20% risk of developing heart disease within 10 years. Women at intermediate risk (10% to 20% 10-year risk) may also take aspirin provided their blood pressure is under control. To find out if you meet the “at risk” criteria, use this risk calculator. People with type 2 diabetes have a high risk of developing heart disease and may be told to take daily aspirin.
Should women at low risk for heart disease take aspirin?
Because many of the early prevention studies on aspirin did not include women, an expert panel noted that the benefits are less established for healthy middle-aged women than for men.18 To address this gap, the Women's Health Study enrolled approximately 40,000 healthy women 45 years of age or older and gave them 100 mg of aspirin or a dummy pill to take every other day.19 After 10 years, there was no difference in the risk of having a heart attack or dying from cardiovascular disease between the two groups. This is in contrast to the benefits seen for healthy men in previous studies. The results did not differ whether women were menopausal or taking hormones, but older age did have an effect. Women taking aspirin who were older than 65 years at the beginning of the study experienced a 34% reduction in the risk of having a heart attack.
Does aspirin prevent stroke?
The Women's Health Study did show that aspirin could prevent stroke, a benefit that has not been shown in men. Women taking aspirin were 24% less likely to suffer ischemic stroke, the most common type of stroke caused by a blood clot in an artery of the brain.19 Because aspirin thins the blood, there was a slight increase in the risk of hemorrhagic stroke or bleeding in the brain; however, this was not statistically significant, and overall aspirin reduced the risk of any stroke by 17%.
How does aspirin work differently in men and women?
Since the Women's Health Study had different results to previous studies in men, researchers decided to further investigate the gender differences. They pooled the results of six studies on aspirin involving almost 95,500 people (more than half were women) who did not already have heart disease, but who may have had risk factors. The results showed that in women aspirin reduced the risk of any stroke by 17%, but did not lower the risk of heart attack.20 Men taking aspirin saw a 32% reduction in heart attack risk, but no stroke benefit.
Aspirin reduced women's risk of the most common type of stroke (ischemic) risk by 24%. For hemorrhagic stoke (one caused by a burst blood vessel in the brain), aspirin had no effect on a women's risk. However, aspirin increased a man's risk of hemorrhagic stroke by 69%. The researchers believe the sex difference may have several explanations. First, women experience more strokes than heart attacks, while men experience more heart attacks than strokes. Second, men and women process aspirin differently; women are more likely to experience aspirin resistance, in which a person's blood does not thin in response to the aspirin.