Why does pre-eclampsia cause vision changes in pregnancy?

Pre-eclampsia may alter blood flow and pressure in areas involved in vision. This can cause blurred or double vision, flashing lights, spots, sensitivity to light or a temporary loss of part of the visual field. These symptoms may come and go or remain present, and they can happen with headache, swelling, upper-abdominal pain or nausea.

Vision changes also have other possible causes, including migraine, changes in the eye itself or low blood sugar. Because sight symptoms can signal a serious pregnancy problem, they should not be diagnosed from symptoms alone. Blood pressure and other checks help guide the next step.

Contact your maternity team immediately for new blurred vision, flashing lights, spots, double vision or a missing area of sight. Sit or lie somewhere safe while you arrange help, note what you can see and when it started, and do not drive while your vision is affected.

Do not wait to see whether the symptom settles after resting. A clinician may need to check blood pressure, urine, blood tests and your neurological or eye symptoms. Bring a list of medicines and describe any headache or abdominal pain at the same time.

Seek emergency maternity care for sudden or ongoing vision loss, severe headache, confusion, weakness, seizure, fainting, severe abdominal pain, breathlessness or reduced fetal movement. These symptoms need prompt assessment even if the visual disturbance improves before you are seen.

Ask: Could my vision symptoms be related to blood pressure? Do I need an eye or neurological assessment? Which warning signs should make me call emergency services? How will my pregnancy be monitored after this episode?