Migraine, low-dose combined hormonal contraceptives, and ischemic stroke in young women: a systematic review and suggestions for future research

Introduction: Migraine and combined hormonal contraceptives (CHCs) increase the risk of ischemic stroke in young women; however, the contribution of low-dose (<50 μg ethinylestradiol) CHCs to the risk of ischemic stroke in young women with migraine is not well defined. Areas covered: The authors performed a systematic review of observational studies indexed in PubMed and Scopus from inception to 22 May 2019, reporting the effect sizes of ischemic stroke in women with migraine using low-dose CHCs compared with those without migraine not using CHCs. All the four included case-control studies, including a total of 12,256 women, reported increased odds of ischemic stroke in women with migraine and low-dose CHC use compared with those without migraine not using CHCs. A meta-analysis was not feasible due to significant heterogeneity. Expert opinion: Strong data on the joint effect of migraine and CHC use on risk of ischemic stroke are lacking especially referring to the role of aura and headache frequency. Evidence suggests that the association with ischemic stroke is driven by migraine with aura. More robust data are needed to assess whether CHCs remain viable for women with migraine without aura, and whether their use could extend to some women with migraine with aura.