103 Migraine with and without aura in relation to the menstrual cycle 5 BACKGROUND Clinical studies suggest a different pathophysiological role for sex hormones in migraine with aura (MA) and without aura (MO). The occurrence of migraine attacks in women is markedly increased around the first days of menstruation.1-3 The risk differs somewhat between different studies, but an increased risk of up to 2.5 times has been described during the perimenstrual window, which is defined as two days before until the first three days of menstruation.1, 4 Migraine attacks starting during the perimenstrual window are associated with higher pain intensity, longer duration and increased recurrence risk, while aura symptoms are suggested to be less common.3, 5 According to the International Classification of Headache Disorders-3 (ICHD-3) appendix criteria, a distinction is made between pure menstrual migraine, i.e. migraine attacks occurring during the perimenstrual window in two out of three menstrual cycles, and at no other times of the menstrual cycle, and menstrually-related migraine, in which attacks may also occur at other times of the menstrual cycle.4 ased on diary data from headache clinics, the prevalence of menstrually-related migraine in women with migraine is approximately 45–66%, whereas pure menstrual migraine is thought to be very rare (<1%).3, 6 In this article the term menstrual migraine is used to cover both menstrually-related and pure menstrual migraine. Note that ‘MO’ and ‘MA’ are used in this article to refer to a migraine diagnosis on a patient level (patients with MO or MA), whereas ‘with aura’ and ‘without aura’ are used to address aura on the level of attacks (migraine attacks with or without aura). In a previous diary study among 81 women, a significantly elevated odds ratio (OR) was observed during the first two days of menstruation for migraine attacks without aura (OR 2.04 [95%CI 1.49–2.81]), but not for attacks with aura, although the odds ratio for attacks with aura also appeared elevated (OR 1.45 [95%CI 0.89–2.36]).7 In a small pilot study among 55 women with migraine, four women fulfilled criteria for pure menstrual migraine.8 All four suffered from MO. In a recent large electronic diary study in a representative group of 500 women, perimenstrual migraine attacks appeared to be less frequently associated with aura symptoms (OR 0.8 [95%CI 0.6–1.0]).5 These clinical observations have led to the hypothesis that fluctuations in hormone levels prior to menstruation increase the susceptibility to migraine attacks without aura, while the evidence regarding attacks with aura remains inconclusive. The appendix of the ICHD-3 contains diagnostic criteria for both menstrual migraine (MM) with and without aura.4 While fluctuations in sex hormone levels are suggested to mainly increase susceptibility to migraine attacks without aura, the opposite is hypothesized to be
RkJQdWJsaXNoZXIy MjY0ODMw