Dizziness in the third trimester

As the uterus grows, lying flat on your back can press on major blood vessels and leave you lightheaded; turning onto your side may relieve it. Standing for a long time, crowded or hot spaces, missed meals and vomiting can also reduce your sense of stability. Anaemia or iron deficiency anaemia can cause dizziness with tiredness or breathlessness. If the sensation is true spinning after head movement, benign paroxysmal positional vertigo is another possibility.

Dizziness is not a diagnosis by itself. Your maternity clinician may consider blood pressure, hydration, blood count, urine symptoms and the baby’s wellbeing according to your situation.

Turn onto your side if lying flat makes you dizzy, then sit up slowly and call for assistance if needed. Rest in a cool place, loosen tight clothing, sip fluids and eat a snack if you have missed food. Avoid ladders, bathing alone and driving during an episode. Keep regular antenatal appointments and report a pattern that is becoming more frequent or harder to recover from.

Seek urgent maternity or emergency care for fainting, a fall, chest pain, difficulty breathing, severe headache, vision changes, new weakness, confusion, vaginal bleeding, severe abdominal pain, or a noticeable change in fetal movement. Contact your maternity team promptly for persistent dizziness, repeated vomiting, marked swelling, a fast or irregular heartbeat or symptoms that do not improve after changing position and resting. Confusion or collapse in heat is an emergency.

Ask which side-lying positions are comfortable, how much fluid and food is suitable for you, whether blood pressure or iron testing is needed, and which symptoms should take you directly to maternity triage.