- Attacks, in a menstruating woman1, fulfilling criteria for 1.1 Migraine without aura and criterion B below
- Occurring exclusively on day 1 ± 2 (ie, days −2 to +3)2 of menstruation1 in at least two out of three menstrual cycles and at no other times of the cycle3.
- For the purposes of ICHD-3, menstruation is considered to be endometrial bleeding resulting either from the normal menstrual cycle or from the withdrawal of exogenous progestogens, as in the use of combined oral contraceptives or cyclical hormone replacement therapy.
- The first day of menstruation is day 1 and the preceding day is day −1; there is no day 0.
- For research purposes a prospective diary is recommended, but this is not mandatory for clinical diagnosis of A1.1.1 Pure menstrual migraine without aura.