The objectives of this prospective, descriptive study are to:
- generate estimates of the incidence, prevalence, persistence, clinical impact and attributable risk of migraine due to hormonal contraception (HC) use; and
- identify predictive factors for clinically significant changes in headache attributable to HC use.
The investigators hypothesize that:
- Most women with pre-existing migraine will have no significant change from baseline headache frequency or clinical impact attributable to HC at 3 months following initiation; a minority will report clinically significant worsening or improvement
- The incidence of headache and migraine in HC users will not be significantly different from their incidence in NHC users
- There will be identifiable risk factors for development or worsening of headache/migraine in the minority of HC users where that occurs.