eclampsia, term applied to toxic complications that can occur late in pregnancy. Toxemia of pregnancy occurs in 10% to 20% of pregnant women; symptoms include headache, vertigo, visual disturbances, vomiting, hypertension, and edema. The four categories of hypertension during pregnancy are pre-eclampsia, eclampsia, chronic hypertension, and transient hypertension. Pre-eclampsia, which occurs late in pregnancy, is characterized by decreased cardiac output and increased blood vessel resistance. It may be prevented with calcium supplements and low-dose aspirin, and a cesarian section is often safer than natural childbirth. Only 5% of of women with pre-eclampsia progress to eclampsia, which is accompanied by convulsions and coma. To avoid renal and cardiovascular damage of the mother and to prevent fetal damage, the condition is treated by termination of pregnancy.

Hypertensive conditions unique to pregnancy. Preeclampsia is marked by hypertension, protein in the urine, and hand and face edema, which develop late in pregnancy or soon after. Persistent hypertension compromises the fetus's blood supply and damages the mother's kidneys. Monitoring of blood pressure and weight gain may detect it before symptoms (headaches, visual disturbances, stomach pain) begin. Eclampsia follows in about 5percnt of cases, with convulsions that pose a serious threat to mother and child. It can usually be prevented by special diets, drugs, and limited activity or early delivery.

Learn more about preeclampsia and eclampsia with a free trial on Britannica.com.

Eclampsia is a serious complication of pregnancy and is characterised by convulsions. Usually eclampsia occurs after the onset of pre-eclampsia though sometimes no pre-eclamptic symptoms are recognisable. The convulsions may appear before, during or after labour, though cases of eclampsia after just 20 weeks of pregnancy have been recorded.

Pathophysiology

The pathogenesis of eclampsia is poorly understood.

Signs and symptoms

The majority of cases are heralded by pregnancy-induced hypertension and proteinuria but the only true sign of eclampsia is an eclamptic convulsion, of which there are four stages. Patients with edema and oliguria may develop renal failure or pulmonary edema.Premonitory stage: this stage is usually missed unless constantly monitored, the woman rolls her eyes while her facial and hand muscles twitch slightly.Tonic stage: soon after the premonitory stage the twitching turns into clenching. Sometimes the woman may bite her tongue as she clenches her teeth, while the arms and legs go rigid. The respiratory muscles also spasm, causing the woman to stop breathing, leading to cyanosis. This stage continues for around 30 seconds.Clonic stage: the spasm stops but the muscles start to jerk violently. Frothy, slightly bloodied saliva appears on the lips and can sometimes be inhaled. After around two minutes the convulsions stop, leading into a temporary unconscious stage.Comatose stage: the woman falls deeply unconscious and needs airway management to allow breathing and prevent hypoxia. This can last only a few minutes or may persist for hours.

Epidemiology

Eclampsia is usually treated well in the majority of cases with just under one in 50 affected women and one in 14 fetuses of affected women developing complications.

Treatment

The treatment of eclampsia consists of preventing further convulsions, controlling elevated blood pressure and delivering the fetus.

Prevention of convulsion is usually done using magnesium sulfate with a loading of Magnesium sulfate 20% solution, 4g IV over 5 minutes, followed by 1g of magnesium sulfate an hour.

The blood pressure may be controlled by hydralazine 5mg IV slowly every 5 minutes until blood pressure is lowered . In less well resourced healthcare settings hydralazine 12.5 mg IM every 2 can be given as needed.

Delivery should take place as soon as the woman’s condition has stabilized. Delaying delivery to increase fetal maturity is unsafe for both the woman and the fetus, after delivery the woman's health will begin to improve. Delivery should occur regardless of the gestational age.

In severe pre-eclampsia, delivery should occur within 24 hours of the onset of symptoms. In eclampsia, delivery should occur within 12 hours of the onset of convulsions. If vaginal delivery is not anticipated within 12 hours (for eclampsia) or 24 hours (for severe pre-eclampsia), deliver by caesarean section.

Bibliography

• Mayes, M., Sweet, B. R. & Tiran, D. (1997). Mayes' Midwifery - A Textbook for Midwives 12th Edition, pp. 533–545. Baillière Tindall. ISBN 0-7020-1757-4