Only right leg swelling during pregnancy: what to know

Pregnancy can cause ankle and leg swelling as the growing uterus affects blood flow and the body retains more fluid. This tends to be mild and may affect both legs. Swelling confined to the right leg, particularly when it appears quickly, can instead reflect a deep vein thrombosis, a blood clot in a deeper vein. Varicose veins can also cause local heaviness, aching, or puffiness. A clot is not confirmed by appearance alone, so an examination is needed.

A swollen ankle may be harmless, but the pattern matters: compare both legs and notice changes in pain, skin colour, warmth, or walking comfort. Related information is available about Swollen Ankles and Varicose Veins.

Contact your maternity team, GP, or an urgent medical service today for advice about new one-sided swelling. Do not massage the swollen area or delay assessment to see whether it settles. Keep a note of when it began, whether it is worsening, and any recent long travel, reduced movement, injury, or previous clot. Continue gentle movement if you are able, but stop if it increases pain. A clinician may decide that you need an ultrasound assessment.

Call emergency services immediately if leg swelling is accompanied by sudden breathlessness, chest pain, coughing blood, faintness, or a racing heartbeat. These symptoms can indicate that a clot has travelled to the lungs. Seek urgent assessment as well for severe leg pain, marked warmth or redness, or rapidly increasing swelling. Do not drive yourself if you feel faint or short of breath.

Ask whether the swelling pattern needs same-day testing, which warning signs should prompt emergency help, and whether your pregnancy or medical history changes your clot risk. Mention any medicines, recent immobility, and previous episodes of swelling.