Pre-eclampsia (US: preeclampsia) is a medical condition where hypertension arises in pregnancy (pregnancy-induced hypertension) in association with significant amounts of protein in the urine. Because pre-eclampsia refers to a set of symptoms rather than any causative factor, it is established that there are many different causes for the syndrome. It also appears likely that there is a substance or substances from the placenta that may cause endothelial dysfunction in the maternal blood vessels of susceptible women. While blood pressure elevation is the most visible sign of the disease, it involves generalized damage to the maternal endothelium and kidneys and liver, with the release of vasopressive factors only secondary to the original damage.