Flashing lights in pregnancy: what to know

Flashes may look like sparks, flickers, or zigzags and may affect one or both eyes. They can occur with migraine or changes inside the eye, but pregnancy changes the safety context. Flashing lights together with a severe headache, blurred vision, upper abdominal pain, sudden swelling, nausea, or feeling unwell can occur with Pre-eclampsia, a condition involving high blood pressure and organ stress. The symptom alone cannot identify its cause, so an examination and blood-pressure check are useful.

Stop driving and sit somewhere safe while you note when the flashes began, how long they last, which eye is affected, and whether headache or other symptoms accompany them. Contact your maternity unit or clinician promptly for new, repeated, or unexplained flashes. Keep taking prescribed medicines unless a clinician tells you otherwise, and do not rely on resting in a dark room as a substitute for assessment.

Seek emergency care for a sudden loss of vision, a curtain or shadow across your sight, severe headache, confusion, weakness, trouble speaking, a seizure, severe abdominal pain, chest pain, or breathlessness. In pregnancy or after birth, visual symptoms with marked swelling or feeling very unwell should be treated as urgent.

Ask whether your blood pressure and urine need checking, whether an eye review is needed, and which warning symptoms should bring you back immediately.