What can cause a severe headache in pregnancy?

A clinician may need to check your blood pressure, urine, neurological symptoms and pregnancy stage. Severity itself is a reason to contact your maternity service now, even if you have experienced headaches before.

Migraine can present with throbbing pain, nausea, light sensitivity or visual aura. Dehydration, missed meals, lack of sleep, viral illness, sinus problems and caffeine withdrawal can also trigger headache. These possibilities cannot safely be distinguished by pain alone.

Pre-eclampsia can present with a severe persistent headache, particularly alongside visual disturbance, pain beneath the ribs, vomiting, sudden swelling or feeling very unwell. It is a pregnancy condition involving high blood pressure and can affect several organs, so assessment should not wait for a routine visit.

Call your maternity unit, obstetric clinician or urgent medical service and describe when the pain started, whether it came on suddenly, where it is located and any accompanying symptoms. Tell them your stage of pregnancy and whether you have high blood pressure, migraine or recent illness.

While arranging advice, rest in a quiet place and drink fluids if you can. Do not start an unfamiliar painkiller or take more than the labelled or prescribed dose; some medicines are unsuitable during pregnancy. A pharmacist or maternity clinician can advise on an appropriate option.

Seek emergency care for a headache that reaches maximum intensity suddenly, follows a head injury, or occurs with fainting, seizure, confusion, weakness, facial droop, difficulty speaking, fever with a stiff neck or loss of vision.

Immediate maternity assessment is also needed for severe headache with blurred vision or flashing lights, pain below the ribs, vomiting, sudden swelling, shortness of breath, vaginal bleeding or noticeably reduced baby movement. Do not drive yourself if you feel faint, confused or unable to see clearly.

Ask whether your blood pressure and urine findings are reassuring, what may be causing the pain, which medicine is suitable in pregnancy and which changes mean you should return. Clarify who to contact if the headache persists or recurs after you go home.