Increased frequency of migraine among women with endometriosis.

BACKGROUND Our aim is to assess the prevalence and characteristics of headache in patients with endometriosis compared with women without this disease. METHODS One hundred and thirty-three women with histologically proven endometriosis and 166 controls were interviewed by a neurologist experienced in headache diagnosis; the headache disorders were classified according to the 1988 International Headache Society criteria. RESULTS The prevalence of migraine was significantly higher among women with endometriosis [n = 51, 38.3%; 95% confidence interval (CI) 30.1-47.2%] than in controls (n = 25, 15.1%; 95% CI 10.0-21.4%) (P < 0.001). Migraine with aura was observed in 18 women with endometriosis (13.5%) and in two controls (1.2%; P < 0.001). The age at migraine onset was significantly lower in women with endometriosis than in controls (16.4 versus 21.9 years; P = 0.001). No significant difference was observed in pain intensity and attack frequency between the two groups; a trend for women with endometriosis to have longer unmedicated attacks was observed. No significant correlation was observed between attack frequency, unmedicated headache duration, migraine intensity and the severity of endometriosis. CONCLUSION Migraine is more frequent in women with endometriosis than in controls, although its presence and characteristics are not related to the severity of endometriosis.