Migraine start, course and features over the cycle of combined hormonal contraceptive users with menstrual migraine - temporal relation to bleeding and hormone withdrawal: a prospective diary-based study.

The day of hormone-withdrawal migraine and the first bleeding day are highly predictable in CHC users. Migraine onset is mostly day - 1 and 1 of the bleeding and on days 1-4 of the hormone-free interval. Migraine attacks of CHC users in the hormone-free interval are severe and long lasting. Further trials are necessary to investigate if this knowledge can be used to optimise prevention.