Migraine Myth of the Month: Migraine Always Improves During Pregnancy
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As with all matters migraine, the problematic word in the title of this month’s myth is “Always”. It can never be emphasized enough: the only thing “always” about migraine is that no aspect of migraine is ever “always”.
The female preponderance of migraine between the ages of 15 and 45 is widely believed to reflect the impact of the monthly fluctuations in sex hormones – especially estrogen – that occur in cycling females. Prior to puberty and following the age when menopause tends to occur, the inequity in migraine prevalence between the two genders flattens out considerably. If migraine is indeed typically, if not always, genetic in origin, it is quite possible that the genetic prevalence of migraine is more or less equal in males and females but that the clinical expression of migraine will be greater in females during their childbearing years consequent to the excitatory effect of fluctuating sex hormone levels upon migraine’s biologic circuitry.
There are certain times during a female’s life when migraine tends to either arise or, if already present, worsen: menarche (the onset of puberty), menses, first trimester pregnancy, the immediate post-partum period and the perimenopausal years. Common to all are the associated changes in sex hormone levels, and it would seem to follow that the stabilization of sex hormone levels that occurs with pregnancy would be paralleled by a progressive reduction in migraine.
While it is generally true that the clinical expression of migraine declines as pregnancy advances and even may be absent altogether during pregnancy, this is far from invariable. A significant minority of migraineurs report no change in their migraine burden with pregnancy. At least 1 in 20 female migraineurs experiences worsening of her migraine during pregnancy, and for some this may persist throughout the full term. Some of the most miserably ill patients that the author has encountered in his clinical practice have been pregnant females literally sick with migraine every day for months on end. Some females may experience their first-ever migraine headaches while pregnant, and some may experience migrainous aura, with or without associated headache, for the first time.
How does one treat a pregnant female’s migraine effectively without potentially causing harm to the fetus? What therapies are known to be “safe” for use during pregnancy? Good questions. Surveying the medical literature to find well-designed prospective studies evaluating the safety of a given migraine therapy in pregnancy is about as futile as searching for a cool freshwater lake in the Sahara. This issues Doctor on Call summarizes the path typically traveled before a new migraine medication comes to be regarded as “acceptable” for use in pregnancy, a consideration of acceptable therapeutic options, and a bit about onabotulinumtoxinA (BotoxA) in particular.
A last word. In no circumstance does a history of migraine guarantee that every headache a migraineur experiences is a consequence of migraine, and that applies in particular to pregnant migraineurs. For example, pre-eclampsia, a potentially quite serious multisystem disorder, can arise unexpectedly in the last half of pregnancy and often begins with persistent headache. While it remains unclear whether migraine may be associated with an increased risk of developing pre-eclampsia, it is a certainty that pregnant migraineurs can develop the disorder. If you are a pregnant migraineur and you experience a significant change in the character or frequency of your headaches – and especially if that change is accompanied by symptoms unusual for you such as visual blurring or focal numbness/weakness, seek medical attention so as to exclude pre-eclampsia and other serious headache-producing conditions that may complicate pregnancy.
