Migraine in pregnancy

Scenario

A 32 year old woman with a history of episodic headache has recently become aware she is pregnant. She has had troublesome headaches from childhood. She has no other medical problems. Her sister and mother have migraines. She is a non-smoker. In the previous five years, her headaches have become more frequent, with five to seven attacks a month of disabling left or right sided, throbbing pain around the parietal and temporal region. The pain is aggravated by physical activity and any movement and associated with nausea and marked vomiting, prominent photophobia, and phonophobia. The attacks last two to three days. She had no aura symptoms. Neurological and general physical examinations were normal, and thus her diagnosis is migraine without aura.2

She has had minimal benefit from over the counter analgesics, including paracetamol (acetaminophen) with and without codeine; aspirin; metoclopramide; prochlorperazine; domperidone; and non-steroidal anti-inflammatory drugs (notably ibuprofen and naproxen). She was started on sumatriptan 20 mg nasal spray. This provided headache relief in about two hours, with some mild chest discomfort. She was also started on topiramate as a migraine preventive, which, at a dose of 50 mg twice daily, reduced her attack frequency to two a month. Breakthrough attacks were treated with sumatriptan. She had some mild paraesthesia with topiramate but no other side effects. This pregnancy, her first, was unplanned. She is currently …