Migraine during pregnancy: options for therapy.

Migraine is common during pregnancy, but fortunately this combination of conditions obviously exists for only a finite period. The greatest frequency of migraine attacks occurs during the first trimester. Accurate diagnosis is a sine qua non in this setting as in any headache patient. It is in the first trimester that the fetus is at greatest risk from abortifacient and teratogenic drugs, and when very early pregnancy may be undiagnosed. Ergot alkaloids (including methysergide) should be avoided during pregnancy because of their teratogenicity, and most other drug classes should be used only when unavoidable. The use of prophylactic agents during pregnancy should be the exception, not the rule, and preferably only during the second and third trimesters; propranolol is probably safest in this situation. De novo headache during pregnancy usually requires expert review of the patient. Treatment tactics for uncomplicated migraine in pregnancy depend on the concurrent clinical situation. Paracetamol (acetaminophen) is the mainstay for the patient whose typical attacks continue into the first trimester. If paracetamol is insufficient, then partial agonist opioids may be used if typical migraine attacks persist in the second and third trimesters (which is uncommon). 'Chronic migraine' in pregnancy, i.e. >or=15 headache days per month, is rare, and is the greatest therapeutic challenge. Co-morbidities such as depression or epilepsy require specialised approaches. The complexities associated with these tactics are discussed in this article, and it is emphasised that none has the specific approval of regulatory authorities. Heightened pharmacovigilance will better inform the future pregnant migraineur. However, this type of information is less likely to be available for novel classes of neuropharmacological agents than for existing ones.