About 1 in 4 maternal strokes associated with migraine traced to hypertensive disorders

Approximately one-fourth of maternal strokes associated with migraine were attributable to a hypertensive disorder, according to data published in JAMA Neurology.

“The relationship between migraine and stroke has never been formally tested and quantified,” Gretchen Bandoli, PhD, assistant professor of pediatrics at the University of California, San Diego, told Healio Primary Care. “Thus, we performed a causal mediation analysis, focused on maternal migraines and strokes in the perinatal period.”

Bandoli and colleagues reviewed birth certificates, hospital discharge summaries and ICD codes from 26,440 women in California who were diagnosed with migraine between 2007 to 2012. They estimated the link between migraine and stroke after adjusting for age, BMI, drug or alcohol use, diabetes, nativity, payer source, mental illness, race/ethnicity and smoking status.

The researchers reported that strokes — 58% of them ischemic — occurred in 843 women (29 per 100,000 deliveries). Women with migraine were more likely to be non-Hispanic white and have private insurance, obesity, preexisting or gestational diabetes, and a mental health disorder. They were also more likely to use tobacco or drugs and alcohol.

Results showed that women with migraine during pregnancy were more likely to have a hypertensive disorder (15.1% vs. 7%; adjusted RR = 1.6; 95% CI, 1.6-1.7), a stroke during pregnancy or delivery (0.15% vs. 0.01%; aRR = 6.8; 95% CI, 4.7-9.8) or a stroke after delivery (0.05% vs. 0.01%; aRR = 2.1; 95% CI, 1.2-3.7) than women without migraine.

The researchers also reported that hypertensive disorders mediated 21% of the risk for stroke during pregnancy and delivery and 27% of the risk for postpartum stroke. The role of hypertensive disorders in all other nonmigraine-related maternal strokes was beyond the scope of the study, according to Bandoli.

“These findings highlight the importance of managing hypertension in pregnancy, particularly among women with migraine,” she said. “However, it simultaneously demonstrates that there are other pathways between migraines and stroke, likely with modifiable targets, that we have not yet discovered.”