Population	• Menstruating women with menstrual or chronic migraine • Postmenopausal women with chronic migraine • Pregnant women with history of migraines • Transgender men and women with history of migraine
Intervention	• Estradiol (injection, percutaneous, etc.) • Hormone replacement therapy • GnRH agonists • Oral contraceptives
Comparison	• Women with non-hormonal chronic migraine • Women with non-menstrual intermittent migraine
Outcomes	• Migraine frequency • Migraine severity • Headache index* • Delay of menstrual migraine • Onset of migraine relative to menstrual cycle

*Headache index is a metric for headache frequency, severity, and duration