Pre-eclampsia is a leading cause of maternal morbidity and mortality [1]. Annually, pre-eclampsia is responsible for 60 000 maternal deaths worldwide and affects 2–3% of all pregnancies [2]. In the UK, although hypertensive disease in pregnancy is a major cause of maternal death, fewer than 10 women die each year, largely due to the antenatal care they receive and timely intervention. However, death rates are no longer falling in the UK [1].