Here’s a man, here’s a woman. How likely is either to have a heart attack? No one knows for sure… but what we do know is that the current tools for predicting heart attack risk are less accurate for women than for men. Now a new study reveals a useful piece of information in this prediction puzzle—a particular type of family history, not of heart attack itself, but of stroke.

Researchers from the University of Oxford analyzed data on 2,210 men and women who had suffered a heart attack or other coronary problem caused by reduced blood flow to the heart. Findings: About 24% of these patients had one or more first-degree relatives (parent, sibling) with a history of stroke. The female heart patients (but not the males) were more than twice as likely to have a mother who’d had a stroke than to have a father who had suffered a stroke. What this means: Maternal stroke history may provide a valuable clue in gauging a woman’s heart attack risk—even though this factor is not currently included in standard heart attack risk assessments.

Best: Women whose mothers suffered a stroke should be especially careful to minimize heart attack risk by getting blood pressure and cholesterol levels checked regularly, exercising, eating healthfully, losing weight if necessary and not smoking.