Summary points

• Pre-eclampsia remains the single most common cause of maternal death in the United Kingdom. Its cause is still unknown so it cannot be prevented or treated rationally

• The rise in blood pressure that occurs in late pregnancy without other symptoms may initially be compensatory for fetoplacental hypoxia and therefore physiological. This compensatory mechanism may explain the high incidence of hypertension during pregnancy

• In some women the compensation breaks down and severe multisystem disease occurs resulting in pregnancy induced hypertension and pre-eclampsia

• Lipid peroxidation and consequent endothelial damage are probably involved in pathogenesis

• Calcium excretion is reduced and intracellular free calcium concentrations increased, which could contribute to the greater pressor responsiveness

• Most of the cardiovascular changes occur during the second half of pregnancy and are hormonally driven rather than mediated by the sympathetic nervous system

• Women at risk of developing pre-eclampsia can be detected early in pregnancy by asking whether their mother developed the condition; by measuring blood pressure using a standardised method; and by checking for proteinuria