Headache
The most common form of headache during pregnancy (as at other times) is chronic daily headache of the tension type. This may be a continuation of pre-existing headaches or a new phenomenon, compounded by anxiety, depression, or poor sleep. Neurological examination is usual in such cases and the treatment should concentrate on explanation and reassurance, coupled if necessary with advice about relaxation techniques. Occasional paracetamol may be helpful; aspirin should be avoided in the third trimester.

Migraine usually improves during pregnancy, but approximately 20 per cent of sufferers get worse and occasionally migraine actually begins in pregnancy. No single hormonal change has been convincingly linked to these divergent responses.

Whilst migraine can generally be identified accurately on clinical grounds, diagnosis is more difficult when it presents for the first time in pregnancy, particularly if accompanied by the transient focal deficits of migraine aura such visual disturbances or hemiplegia. Other potential causes of headache in pregnancy, such as eclampsia, subarachnoid haemorrhage, cerebral venous thrombosis, cerebral infarction, intracranial tumour, and intracranial infection must be considered and excluded by careful neurological and general examination, supplemented if necessary by brain imaging (see below). Some women present in pregnancy with migraine aura without headache, which can also give rise to diagnostic difficulty: it may be necessary to exclude causes of transient ischaemic attack.

Acute migraine attacks should be treated promptly with rest and paracetamol; prochlorperazine is probably a safe treatment for vomiting. Ergot derivatives must be avoided in pregnancy (and breastfeeding), and the triptan drugs have not yet been shown to be safe. If attacks are frequent then attention should be paid to relevant lifestyle factors such as irregular sleep or meals and worry. Prophylactic drug treatment is occasionally necessary, and the greatest experience lies with propranolol which, in doses of 20 to 80 mg three times a day, appears to be both effective and safe, despite its effect on placental blood flow. Women with migraine commonly develop a dull non-specific headache of variable severity in the first few days after delivery. This usually responds to simple analgesia, particularly if the woman has been warned about the phenomenon.