Eclampsia is characterized by convulsive seizures in women during late pregnancy. It is preceded by preeclampsia, which develops in 5 percent of pregnant women and is characterized by hypertension (high blood pressure), edema (swelling), and proteinuria (excretion of protein in the urine). The cause of preeclampsia is unknown; untreated, it will progress to eclampsia in 5 percent of the cases. The incidence of preeclampsia is reduced with weight control. Labor is usually induced when eclampsia occurs, because the convulsions endanger both the mother and the fetus. Eclampsia accounts for 5 percent of maternal deaths and 40 percent of fetal deaths.