What causes pre-eclampsia?

Pre-eclampsia remains a leading cause of maternal and fetal morbidity and m ortality. Despite extensive research, the mechanisms that cause pre-eclamps ia are unknown and it has been considered to be. the 'disease of theories'. Hippocrates wrote in one of his Aphorisms that 'convulsions take place fro m either repletion or depletion'. Since then, obstetricians have been divid ed on the question of which factor accounted for the convulsions observed d uring childbirth. Some considered that a sudden reduction in intraabdominal pressure at delivery led to a pooling of blood diverted from the brain, ca using collapse of the cerebral blood vessels and convulsions. Others postul ated that cerebral congestion, secondary to compression of the abdominal or gans by the large uterus, diverted blood to the brain, causing eclamptic co nvulsions. it is the purpose of this review to examine those theories about the cause of pre-eclampsia for which modern evidence is available. At pres ent, it is believed that the pathological chain of events leading to preecl ampsia is scheduled in two steps: an absolute or relative placental ischaem ia is followed by a diffuse endothelial cell activation, which causes the c linical features of the disease.