Pre-eclampsia is a heterogeneous disorder affecting 3-5% of pregnancies worldwide. For the fetus, preeclampsia can result in small -for gestational - age infancy, preterm delivery, hypoxic neurologic injury or death. For the mother, complications of preeclampsia include renal failure, HELLP syndrome, seizures, liver failure, stroke or death. Women with preeclampsia often later develop cardiovascular disease and hypertension, another source of significant morbidity.An abnormally developed, hypoxic placenta and endothelial dysfunction are important themes. Further, there seems to be a tip in the balance of angiogenesis versus antiangiogenesis, with favoring of the latter in pre-eclampsia.Eventhough the pathogenesis of illness has been determined after many studies .its etiology is still unknown , certain theories have been put forward in this regard : endothelial cell damage , decreased placental perfusion , changed vascular activity , instability between prostacycline , and thromoxane , genetic factors , increased neural system irritability, and uterine ischemia .Renine – angiotensin – aldosterione system related vascular and haemostatic hyperactivity , thrombocytes and eicosaniods have also blamed for this disease.