The effects of oral contraceptives on detection and pain thresholds as well as headache intensity during menstrual cycle in migraine.

BACKGROUND: Clinically, oral contraceptives (OC) can influence pain in both migraine headache and temporomandibular pain disorders. Estrogen as an ingredient of OC might be a responsible factor for these observations. We conducted the present study to test whether OC are able to alter the severity of headache attacks as well as the detection or pain thresholds over the course of the menstrual cycle in patients with migraine.

METHODS: Thirteen healthy and regularly menstruating women and 26 migraineurs (13 using OC and 13 not using OC) were studied on the days 1, 4, 14, and 22 of their menstrual cycle. In all participants, saliva was collected first for determination of estrogen on each study day. Then, detection thresholds (warmth, cold, electrical current) and pain thresholds (cold, heat, pressure, electrical current) were assessed. Migraineurs were asked for headache attacks occurring in a period of 24 hours before testing and to estimate pain intensity on a verbal rating scale.

RESULTS: On day 4 of the menstrual cycle, migraineurs using OC suffered significantly more from severe migraine attacks than migraineurs not taking OC. With respect to detection and pain thresholds, no effects of OC could be observed as concerning the differences between migraineurs with or without OC medication. On day 22, the severity of migraine headache was significantly related with the pain thresholds for pressure and electrical current, suggesting paradoxically more severe headache attacks in patients presenting with higher pain thresholds. Healthy volunteers disclosed higher salivary estrogen levels than migraineurs and migraineurs not using OC higher concentrations than migraineurs using OC throughout the menstrual cycle.

CONCLUSIONS: In this study, the use of OC intensified migraine (however only at the end of menstruation) however had no influence on detection and pain thresholds in migraineurs. Possible reasons for this dissociation will be discussed.