Migraine in women with endometriosis

Abstract

The objective of the current study is to compare the prevalence and characteristics of different types of headache between women with and without endometriosis. Observational study. The subjects of the study were recruited among women of reproductive age undergoing surgery because of benign gynaecological conditions. The subjects identified as suffering headaches were interviewed by a neurologist. The type of headache was classified according to the 1988 International Headache Society criteria. Age at onset, headache frequency, duration of headache (unmedicated), pain intensity, and specific headache features were investigated. The interview included questions on demographic (age, race) and health characteristics / behaviours (height, weight, alcohol use, smoking status, oral contraception). The subjects were also asked if they had ever consulted a physician for headache. The neurologist who performed the interview was not aware of the gynecologic problem of the patients, and in all cases the interview was performed before surgery. The diagnosis of endometriosis was always histologically confirmed; its extent was scored according to the revised classification of the American Fertility Society (rAFS). Patients complaining pelvic pain and / or dysmenorrhoea were asked to rate the intensity of the symptoms on a 10-point ranked ordinal scale. Data were analysed by using the Student's t test, the Mann-Whitney U test, and the χ2-test. 133 women with endometriosis and 166 controls were included in the study. There were no significant differences in demographic and health characteristics between the two groups. The prevalence of headache was significantly higher among women with endometriosis (n = 85, 63.9%; 95% CI, 55.1 − 72.1%) than in the control group (n = 60, 36.1%; 95% CI, 28.8 − 44.0%) (p<0.001; 22.8, χ2). When the different types of headaches were considered, only migraine (both with and without aura) was significantly more frequent among women with endometriosis (n = 51, 38.3%; 95% CI, 30.1 − 47.2%) than in the control group (n = 25, 15.1%; 95% CI, 10.0 − 21.4%) (p<0.001; 21.1, χ2). No significant difference was observed in the prevalence of migraine among women with mild (15/39, rAFS I-II) and severe endometriosis (36/94, rAFS III-IV). Migraine intensity did not correlate with the intensity of pelvic pain or dysmenorrhoea. The age at migraine onset was significantly lower in women with endometriosis than in controls (p = 0.001). Among subjects with migraine, the mean intensity of pain was similar in women with and without endometriosis; 41.2% (n = 21) women with endometriosis and 32.0% (n = 8) controls reported very high levels of pain (9 to 10 on a 10-point scale). No significant difference was observed in the migraine attack frequency between women with and without endometriosis; 64.7% (n = 33) women with endometriosis and 64.0% (n = 16) controls reported more than one migraine attack per month; 15.7% (n = 8) women with endometriosis and 16.0% (n = 4) controls reported one or more migraine attacks per week. There was a trend for women with endometriosis to have longer attacks than control subjects. 47.1% of women with endometriosis and 48.0% of controls reported to suffer headache during each menstrual cycle. The presence of migraine should always be investigated in women with endometriosis because they have a significantly higher prevalence of this type of primary headache than the general population.