Migraine headaches and obesity are both prevalent disorders, resulting in a high socioeconomic burden. To better understand the relationship between obesity and migraine, the aim of this study was to investigate the association between migraine severity, metabolic syndrome and estrogen-associated variables. A retrospective analysis of adult patients with refractory migraine seen by our senior author (J.E.J.) was performed. Patient demographics and migraine characteristics, including migraine intensity, duration, and number of headaches per month were collected from medical records. Migraine headache index (MHI) was calculated by multiplying frequency, intensity and duration of headaches. Weight and height were used to calculate body mass index (BMI) and these were divided per Center for Disease Control (CDC) classifications. Univariate linear regression models were used to evaluate associations. Patients (n = 223) were predominantly female (78%) with a mean age of 44 years at presentation. Patients with a BMI higher than 40 (class 3 obesity) had a higher MHI (p = 0.01) and experienced a higher number of migraines per month (p = 0.007), compared to patients with a healthy BMI, respectively. Migraine frequency was found to be significantly higher in post-menopausal women compared to pre-menopausal women (p = 0.02). No other significant associations were found. This study found that severe obesity (BMI > 40) is associated with increased migraine severity and frequency. Post-menopausal patients are also found to have increased migraine frequency, which could be explained by the estrogen-withdrawal hypothesis. Future studies are needed to evaluate the outcomes of individuals with obesity after nerve deactivation surgery.Copyright © 2023 Elsevier Ltd. All rights reserved.