Hypertension is the most common medical complication of pregnancy, affecting 8-10% of pregnancies in the UK. It is associated with risks to both the woman and the fetus, with increased risks of pre-eclampsia, preterm delivery, fetal growth restriction, placental abruption and perinatal death. Any new onset of hypertension after 20 weeks or symptoms or signs suspicious of pre-eclampsia should be referred for same day assessment at a secondary care antenatal assessment unit.