Reports

New Research Links Birth Control to Increased Stroke Risk: What Women Should Know

The findings come from the Secreto study, a large-scale investigation into unexplained strokes in people aged 18 to 49 across 13 European countries. Among 608 patients studied, researchers discovered that women taking combined oral contraceptives were three times more likely to suffer from a cryptogenic stroke compared to non-users—even after controlling for other risk factors like obesity and migraines.

• By Newsdesk
• New Delhi
• Jun 01, 2025

Reports

Millions of women rely on combined hormonal contraceptives every day—for birth control, cycle regulation, and hormone balance. But emerging research is shedding light on a potentially serious, and often underestimated, risk: stroke.

Presented at the 2024 European Stroke Organisation Conference, new findings from an international study suggest that women who use combined oral contraceptives—those containing both synthetic oestrogen and progestin—may face a significantly increased risk of cryptogenic stroke. This type of stroke, which occurs with no identifiable cause, accounts for roughly 40% of strokes in younger adults, with women appearing to be disproportionately affected.

A Closer Look at the Findings

The findings come from the Secreto study, a large-scale investigation into unexplained strokes in people aged 18 to 49 across 13 European countries. Among 608 patients studied, researchers discovered that women taking combined oral contraceptives were three times more likely to suffer from a cryptogenic stroke compared to non-users—even after controlling for other risk factors like obesity and migraines.

This is not the first time hormonal contraceptives have been associated with cardiovascular risks. A separate study published earlier this year tracked over two million women and found that combined hormonal methods—including pills, patches, vaginal rings, and some IUDs—were linked to increased risks of both stroke and heart attack.

In that study, the vaginal ring was associated with a 2.4-fold increase in stroke risk and a 3.8-fold increase in heart attack risk, while the contraceptive patch raised stroke risk by 3.5 times. Notably, progestin-only contraceptives, such as certain IUDs, did not show the same elevated risk, highlighting oestrogen as a likely contributor.

Why Oestrogen Matters

The synthetic oestrogen in hormonal contraceptives is more potent and consistently delivered than the body’s natural hormone levels. While oestrogen plays a vital role in regulating blood clotting—a necessary function for healing—it also stimulates the liver to produce more clotting proteins while reducing natural anticoagulants. This shift makes blood clots more likely to form, which can in turn lead to ischaemic strokes, the most common kind, caused by blocked blood flow to the brain.

In addition to increasing clotting, oestrogen may slightly raise blood pressure and affect how blood vessels function over time—further contributing to stroke risk.

These physiological effects are especially concerning for individuals who already have other stroke risk factors, such as smoking, a personal or family history of clotting disorders, or chronic migraines.

Putting the Risk in Perspective

While the headlines can be alarming, experts stress that the absolute risk of stroke for any one woman remains low. For example, the likelihood of a woman on the combined pill experiencing a stroke is estimated to be about 1 in 4,700 per year.

Still, when millions of women around the world use combined hormonal contraceptives, even a small increase in individual risk can lead to a significant number of strokes on a population level—particularly among younger women, where cryptogenic strokes are more common.

An Unfinished Conversation in Women’s Health

The conversation around birth control and stroke risk also points to a broader issue: the underrepresentation of women in medical research. For decades, most clinical trials focused on male physiology, often excluding women entirely or not analyzing sex-specific outcomes. As a result, the full spectrum of side effects associated with hormonal contraception remains under-researched and under-communicated.

This knowledge gap limits women’s ability to make fully informed decisions about their reproductive health—and reinforces a system where side effects are often downplayed or normalized.

“Women deserve transparency about the risks and benefits of every contraceptive option,” say health advocates. “That starts with access to accurate, unbiased information—and a healthcare system that listens and invests in research designed for women’s bodies.”

The Bottom Line

No contraceptive method is without trade-offs. While combined hormonal contraceptives are effective and convenient, they may pose a higher risk of stroke—especially for those with additional risk factors. But it’s also important to remember that pregnancy and postpartum recovery carry even higher risks of clotting-related complications.

Ultimately, the goal isn’t to discourage contraceptive use, but to empower women with complete, evidence-based information so they can choose the method that best aligns with their health, values, and lifestyle.

As the science evolves, one thing remains clear: more inclusive research and better-informed conversations are key to safer and more equitable healthcare for women everywhere.