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.Drife JO, Magowan (eds). Clinical Obstetrics and Gynaecology, chapter 39, pp 367-370. ISBN 0-7020-1775-2. 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.

Pre-eclampsia may develop from 20 weeks gestation (it is considered early onset before 32 weeks, which is associated with increased morbidity) and its progress differs among patients; most cases are diagnosed pre-term. Apart from abortion, Caesarean section, or induction of labor, and therefore delivery of the placenta, there is no known cure. It may also occur up to six weeks post-partum. It is the most common of the dangerous pregnancy complications; it may affect both the mother and the fetus.

Diagnosis

Pre-eclampsia is diagnosed when a pregnant woman develops high blood pressure (two separate readings taken at least 4 hours apart of 140/90 or more) and 300 mg of protein in a 24-hour urine sample (proteinuria). A rise in baseline BP of 30 systolic or 15 diastolic, while not meeting the absolute criteria of 140/90 is still considered important to note but no longer diagnostic. Swelling, or edema, (especially in the hands and face) was originally considered an important sign for a diagnosis of pre-eclampsia, but in current medical practice only hypertension and proteinuria are necessary for a diagnosis. However, pitting edema (unusual swelling, particularly of the hands, feet, or face, notable by leaving an indentation when pressed on) can be significant, and should be reported to a health care provider.

Although eclampsia is potentially fatal, pre-eclampsia is often asymptomatic, hence its detection depends on signs or investigations. Nonetheless, one symptom is crucially important because it is so often misinterpreted. The epigastric pain, which reflects hepatic involvement and is typical of the HELLP syndrome, may easily be confused with heartburn, a very common problem of pregnancy. However, it is not burning in quality, does not spread upwards towards the throat, is associated with hepatic tenderness, may radiate through to the back, and is not relieved by giving antacids. It is often very severe, described by sufferers as the worst pain that they have ever experienced. Affected women are not uncommonly referred to general surgeons as suffering from an acute abdomen, for example acute cholecystitis.