OBJECTIVE: To examine the headache characteristics of women with migraine and 
endometriosis (EM), and differences in the prevalence of comorbid conditions 
between female migraineurs with EM, without EM and nonheadache controls.
BACKGROUND: Migraine and EM are common conditions in women of reproductive age, 
and both are influenced by ovarian hormones. The comorbidity of migraine and EM 
is newly recognized, but reasons for the association are uncertain.
METHODS: This is a cross-sectional study of female headache outpatients and 
healthy controls conducted at University of Toledo and Duke University in 2005 
and 2006. After a headache specialist determined headache frequency and 
diagnosis (based on criteria of the second International Classification of 
Headache Disorders), patients completed a self-administered electronic survey 
with information on demographics, headache-related disability, menstrual 
disorders, premenstrual dysphoric disorder (PMDD), vascular event risk, and 
comorbid conditions, including irritable bowel syndrome (IBS), fibromyalgia 
(FM), chronic fatigue syndrome (CFS), interstitial cystitis (IC), depression, 
and anxiety.
RESULTS: Study enrolled 171 women with migraine and 104 controls. EM was 
reported more commonly in migraineurs than in controls (22% vs 9.6%, P < .01). 
Frequency of chronic headache was higher in migraineurs with EM compared to 
without EM (P= .002) and median headache-related disability scores were also 
higher in the EM group (P= .025). Symptoms of PMDD were more common in 
migraineurs, but frequency did not differ by EM status. Migraineurs with EM 
reported more menorrhagia, dysmenorrhea, and infertility compared to the 
migraine cohort without EM and to controls. Depression, anxiety, IBS, FM, CFS, 
and IC were more common in migraine with EM group than in controls. Anxiety (OR 
= 2.2, 95% CI 1.0-4.7), IC (OR = 10.6, 95% CI 1.9-56.5), and CFS (OR = 3.6, 95% 
CI 1.1-11.5) were more common in migraine with EM group, than in the cohort with 
migraine without EM.
CONCLUSION: Prevalence of EM is higher in women with migraine than in 
nonheadache controls. Migraineurs with EM have more frequent and disabling 
headaches, and are more likely to have other comorbid conditions affecting mood 
and pain, compared to migraineurs without EM.