Table 2 IHS classification (ICHD-3) for exogenous hormone-induced headache and estrogen-withdrawal headache

A. Headache or migraine fulfilling criteria C and D

A. Headache or migraine fulfilling criteria C and D

B. Regular use of exogenous hormones

B. Daily use of exogenous estrogen for ≥3 weeks, which has been interrupted

C. Headache or migraine develops or markedly worsens within 3 months of commencing exogenous hormones

C. Headache or migraine develops within 5 days after last use of estrogen

D. Headache or migraine resolves or reverts to its previous pattern within 3 months after total discontinuation of exogenous hormones

D. Headache or migraine resolves within 3 days of its onset