Daily Dose: Migraine without Aura Raises Stroke Risk for Women on Combined Hormonal Contraceptives

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On May 22, 2023, we reported on a study published in Headache that examined whether migraine history compounds stroke risk in combined hormonal contraceptives (CHC) users and whether stroke risk differed based on more commonly used doses of ethinyl estradiol (EE) dose (30–35 vs <30 μg EE).

The study

The case-controlled study included 203 853 women cared for in a large urban academic tertiary care center, aged 18 to 55 years who had used CHCs between Jan. 1, 2010, to Dec. 31, 2019.

The findings

Overall, 127 women had confirmed cases of stroke while taking CHC at the time and were placed into the case cohort, while 635 women were placed into a control cohort. The investigators found that on average, women who had experienced a stroke while on CHC were overweight (mean BMI 29.4 kg/m2), White (84%), and had never smoked (70%). While obvious risk factors for stroke were not common, among those that were identified, the most common was hypertension (35%), followed by hyperlipidemia (16%), and diabetes (12%).

Results showed that a higher proportion of patients in the case cohort had a diagnosis of migraine (26.8%) compared with those in the control cohort (17.3%). Also, among the case cohort, 11.0% reported migraine with aura vs 8.5% of controls; 15.7% of the case cohort reported migraine without aura versus 8.7% of controls.

Investigators reported that use of a CHC with an EE dose ≥of 30 μg was more common among participants in the case cohort vs those in the control group (62.2% vs. 51.7%; P=0.030). Patients who received an EE dose ≥30 μg had an increased risk for stroke compared with those prescribed <30 μg EE (OR=1.52; 95% CI, 1.02-2.26).

Additionally, the odds of stroke among participants with a history of migraine were 2 times that of those with no history of migraine (OR, 2; 95% CI, 1.27-3.17).

However, when they compared participants with migraine with those with no migraine history, the researchers found that stroke risk was only significant in those with migraine without aura (OR=2.35; 95% CI, 1.32-4.2), not among those with migraine with aura.

Clinical implications

"Our findings highlight the importance of appropriate patient education and shared decision-making for all women who start a CHC with a history of migraine, even those without aura. Women with migraines who prefer to be on estrogen-containing contraceptives for pregnancy prevention or a medical need should consider options that have <30 μg EE, and possibly <20 μg, if medically appropriate."

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