Women who use combined hormonal contraceptives (CHC) and have migraine with aura are 6 times more likely to experience an ischemic stroke than women who do not have either risk factor, according to a study published in the American Journal of Obstetrics and Gynecology.
Almost half of women experience migraine in their lifetime, and 1 in 3 have migraine with aura. Migraine is linked with an increased risk of ischemic stroke among women of reproductive age, one-third of whom use CHCs that contain estrogen and progestin. CHC use further increases the risk of stroke in women with migraine, but the effect of CHC use on stroke risk according to migraine type (with aura or without aura) was not established until recently.
Naomi Tepper, MD, MPH, and colleagues from the Centers for Disease Control and Prevention evaluated the impact of CHC use and migraine type on the risk of ischemic stroke using data from women of childbearing age (15 to 49 years) from a healthcare claims database.
A total of 25,887 ischemic strokes were identified among 33,218,977 women, yielding a cumulative incidence of 11 strokes per 100,000 women per year. The incidence of stroke was lowest in the youngest women (ages 15 to 19 years) and highest in the oldest age group (ages 45 to 49 years).
Both migraine with aura and migraine without aura were associated with an increased risk of ischemic stroke compared with no migraines (adjusted odds ratio [OR], 2.9 and 2.1, respectively), with migraine with aura found to be a stronger risk factor for stroke than migraine without aura.
CHC use modestly increased the risk of ischemic stroke compared with no CHC use (adjusted OR, 1.3).
The combination of CHC use and migraine with aura was a significant predictor for ischemic stroke, increasing the risk of stroke 6-fold compared with the combination of no CHC use and no migraines (adjusted OR, 6.1).
Migraine with aura remained a risk factor for ischemic stroke among women who did not use CHCs (adjusted OR, 2.7). CHC use did not increase stroke risk among women with migraine without aura (adjusted OR, 1.8 for CHC use and 2.2 for no CHC use).
“Determining migraine type — with or without aura — is critical when assessing safety of CHCs among women with migraine,” Dr Tepper said in an interview with Neurology Advisor. “Clinicians can consider consulting guidelines on headache classification or headache specialists.”
Dr Tepper noted that further studies are needed to examine the risk of ischemic stroke in women with migraine without aura, which was increased regardless of CHC use. “Studies should also examine whether progestin-only contraceptives are associated with any increased risk among women with migraine,” she added. “Evidence has not demonstrated an increased risk of ischemic stroke with use of progestin-only contraceptives; however there is limited evidence, particularly among women with risk factors for stroke, such as migraine with aura.”
Champaloux SW, Tepper NK, Monsour M, et al. Use of combined hormonal contraceptives among women with migraines and risk of ischemic stroke [published online December 26, 2016]. Am J Obstet Gynecol. doi: 10.1016/j.ajog.2016.12.019