Women using combined oral contraceptives, commonly known as the birth control pill, face a tripled risk of stroke, affecting roughly six in 100,000 young women annually. However, the absolute danger remains small, according to findings from a 14-country European study.
The research, presented at the European Stroke Organization Conference (ESOC) 2025, analyzed data from more than 500 women across 14 European medical centers.
Researchers found that women between 18 and 49 years who used combined oral contraceptives had triple the odds of experiencing cryptogenic ischemic stroke, a type of stroke with no identifiable cause, compared to women who did not use the pills.
However, medical experts emphasize that the absolute risk remains low. “Even a tripling of risk may mean going from something like two strokes per 100,000 young women per year to six per 100,000,” Dr. Rayan Elkattah, a minimally invasive gynecologic surgeon at Iris Wings Sanctuary for Endometriosis Surgery & Wellness, and not involved in the study, told The Epoch Times. “That’s still far less risk than many common lifestyle factors like smoking or obesity.”
One Hormone in Pill Especially Linked to Risk
The study, called the SECRETO project, involved 268 women who had experienced cryptogenic stroke and 268 women without any stroke history.
After adjusting for factors such as age, high blood pressure, smoking, migraines with aura, and belly fat, the researchers still observed increased risk.
“Our findings confirm earlier evidence linking oral contraceptives to stroke risk,” study lead author Dr. Mine Sezgin, a neurologist at Istanbul University, said in a statement. “What’s particularly notable is that the association remained strong even when accounting for other known risk factors, which suggests there may be additional mechanisms involved—possibly genetic or biological,” she noted.
Most women in the study who used oral contraceptives were taking formulations that contained a hormone called ethinylestradiol, with a typical dose of 20 micrograms, which is considered low-dose by current standards. According to the most recent guidelines, women should be prescribed contraceptives with 35 micrograms of ethinylestradiol or less.
Furthermore, the data regarding the safety of 20 micrograms of ethinylestradiol versus 25, 30, or 35 micrograms suggest less risk with 20 microgram formulas.
The way risk develops may be linked to estrogen’s tendency to promote inflammation and blood clotting. However, the overall level of risk remains unclear because estrogen can have different effects depending on the dose.
The findings come as stroke rates among younger adults have increased since the 1980s, despite an overall decline in stroke cases across high-income countries. Cryptogenic strokes represent 30 to 50 percent of all ischemic strokes among young adults, according to Dr. Achillefs Ntranos, founder of Achilles Neurology Clinic, who was not involved in the research.
“Strokes in younger adults, ages 18 to 49, have actually risen since the 1980s, now making up about 10 to 15 percent of all strokes in the U.S.,” Ntranos told The Epoch Times.
Research suggests this is because estrogen, at certain doses, can promote blood clotting and potentially elevate blood pressure.
Clinical Implications and Alternatives
The researchers advise health care providers to be cautious when prescribing combined oral contraceptives to women who have other risk factors for blood vessel problems or previous strokes. “Our findings should prompt more careful evaluation of stroke risk in young women, particularly those with additional risk factors,” Sezgin stated.
For women concerned about the risk, Elkattah advises considering non-estrogen contraceptive methods, such as progestin-only pills (mini-pills), hormonal IUDs, copper IUDs, and implants or injections such as Depo-Provera.
“While the findings don’t drastically change current prescribing practices, they clearly suggest that not all contraceptive methods carry the same level of risk,” Ntranos said.
Balancing Risks and Benefits
Medical experts caution against discontinuing contraceptive use based solely on these findings.
“For most young, healthy, non-smoking women who don’t experience migraines with aura or have other significant vascular risk factors,” Ntranos said. “Combined oral contraceptives remain generally safe and highly effective.”
However, he added, the findings “underline the necessity of a personalized approach rather than a one-size-fits-all policy.”
The research adds to ongoing discussions about contraceptive safety.
Previous research has linked the use of oral contraceptives containing more than 50 micrograms of ethinylestradiol to increased stroke risk. The U.S. Food and Drug Administration has identified health problems potentially linked to use of hormonal contraceptives, including heart arrhythmias, stroke, blood clots, embolisms, and sudden death.
The current study suggests that even reduced-dose pills may carry some risk.
Sezgin stated that while the findings offer important initial insights, larger studies are needed to determine if certain pill types carry different risks—information that could help doctors tailor contraceptive choices more safely for women.
Moving forward, Sezgin and team plan to explore potential biological and genetic reasons to explain the observed link between birth control pills and increased stroke risk to understand how these medications might elevate risk.
