OverviewHeadache is a common condition affecting the majority of women at some time in their lives. Epidemiological studies of migraine also confirm that up to one-third of women will experience migraine, particularly during their fertile years. Studies suggesting that migraine in young women is associated with an increased risk ischaemic stroke have led to particular concerns regarding the additional effect of other risk factors such as use of combined oral contraceptives (COCs).This paper reviews the effect that COCs have on headache and migraine and considers the data on the risk of ischaemic stroke in COC users with migraine. This evidence will be used to support practical guidance on the management of women with migraine wishing to use COCs.Whilst the evidence presented is based on studies of COCs, there is no evidence to suggest that the effects of other combined hormonal contraceptives (CHCs) are any different. Until further data are available on the different routes of delivery, the following recommendations apply to all CHCs.
Search strategyA MEDLINE search from 1950 to April 2007 using the search terms 'headache', 'migraine', 'contraception', 'ethinyl(o)estradiol', 'progestogen', 'progesterone', '(o)estrogen', '(o)estradiol' and 'isch(a)emic stroke' identified 272 publications, which were scrutinised for relevancy to this review.In addition, references from the author's own files, a hand-search of the journals Cephalalgia and Headache, and peer-reviewed presentations at international congresses were considered.
Effect of COCs on headacheHeadache is a common condition in the absence of COC use. In order to assess its true relationship to COCs, baseline assessment and placebo-controlled trials are necessary.Studies reviewing headache over time suggest that initial exacerbation in the early cycles of use is followed by resolution with continued use. 1-3 If headache occurs, it is most likely to be during the hormone-free interval. [4][5][6] Of 3679 women starting COCs for the first time, using 20 µg ethinylestradiol (EE) and 150 µg desogestrel, 36% reported headache at baseline. 2 After three cycles, 14% reported that headache had worsened, 57% reported improvement and 28% reported no change. New onset of headache affected only 0.5%.In a study of 3267 women starting a COC containing 30 µg EE and 75 µg gestodene, 46% were first-time COC users and 54% were switching from another brand. 3 Of the 16% of women with headache at baseline, 63% reported improvement over the 18-cycle study. New onset of headache was reported by 8.8% of women in cycles 1 to 3, 3.9% in cycles 4 to 6, 3.9% in cycles 10 to 12, and 2% in cycles 16 to 18. There was no analysis of new users versus switchers.In addition, frequency of headache may depend on the type of progestogen and the dose of oestrogen used. Studies of COCs containing 30 µg EE and levonorgestrel (a second-generation progestogen) note headache in approximately 10% of all cycles. 7 It might appear that use of COCs containing third-generation progestogens is associated with...