Young women who use combined oral contraceptives (OCs) may face a threefold increase in the risk of cryptogenic ischaemic stroke, according to new research presented at the European Stroke Organisation Conference (ESOC) 2025.
The findings add to growing concerns about the vascular risks associated with hormonal birth control, particularly for women of reproductive age. Cryptogenic ischaemic stroke—defined as a stroke with no identifiable cause—makes up nearly 40% of ischaemic strokes among young adults, yet the role of sex-specific risk factors like contraceptive use has remained underexplored.
This new analysis comes from the Searching for Explanations for Cryptogenic Stroke in the Young (SECRETO) study. Researchers compared 268 women aged 18 to 49 who had experienced cryptogenic strokes with 268 age-matched women without stroke across 14 European medical centers.
Of the participants, 66 stroke patients and 38 control subjects were using combined oral contraceptives. After adjusting for other known stroke risk factors—such as smoking, high blood pressure, migraine with aura, and obesity—OC users were found to have three times the odds of suffering a stroke (adjusted odds ratio: 3.00; 95% CI: 1.61–5.57).
Lead investigator Dr. Sezgin noted that the increased risk appeared to be independent of other health conditions. “There were no significant interactions between contraceptive use and other risk factors,” she said. “This suggests the stroke risk may be directly related to the hormonal components in these contraceptives.”
Most of the women were taking formulations containing ethinylestradiol, a synthetic estrogen, with a median dose of 20 micrograms. Some were using other forms of estrogen, such as estradiol hemihydrate or estradiol valerate. The research team adjusted the estrogen dose in their analysis to ensure consistent comparisons.
“While our findings offer early insight, larger studies are needed to assess whether different types or doses of hormonal contraceptives carry varying levels of risk,” said Dr. Sezgin. “This could help clinicians offer more personalized contraceptive guidance.”
Although the study was observational and cannot prove causation, the researchers advise caution when prescribing combined OCs to women with existing vascular risk factors or a history of stroke. They emphasize the importance of evaluating stroke risk more carefully in women considering hormonal contraception.
Future research will aim to uncover the biological and genetic mechanisms behind this association, in hopes of understanding how hormonal contraceptives may independently influence stroke risk in women.
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