Eclampsia (toxaemia of pregnancy) is a rare but very serious disease that occurs only in pregnancy. In developed countries it is very uncommon, because most women undertake regular antenatal visits and checks.
Pre-eclampsia is a condition that precedes eclampsia, and this is detected in about 10% of all pregnant women. The correct treatment of pre-eclampsia prevents eclampsia.
The exact cause of pre-eclampsia is unknown, but it is thought to be due to the production of abnormal quantities of hormones by the placenta. This in turn may be due to a poor blood supply to the placenta, or mother’s kidneys liver or brain. It is more common in first pregnancies, twins and diabetes.
Pre-eclampsia normally develops in the last three months of pregnancy, but may not develop until labour commences, when it may progress rapidly to eclampsia if not detected. The early detection of pre-eclampsia is essential for the good health of both mother and baby.
Doctors diagnose the condition by noting high blood pressure, swollen ankles, abnormalities (excess protein) in the urine due to poor kidney function and excessive weight gain (fluid retention). Blood tests may show a low level of platelets (thrombocytopenia) that are used in blood clot formation. Not until the condition is well established does the patient develop the symptoms of headache, nausea, vomiting, abdominal pain and disturbances of vision.
If no treatment is given, the mother may develop eclampsia. This causes convulsions, coma, strokes, heart attacks, death of the baby and possibly death of the mother. Pre-eclampsia is treated by strict rest (which can be very effective), drugs to lower blood pressure and remove excess fluid, sedatives, and in severe cases, early delivery of the baby. An infusion of magnesium sulphate into a vein may be used while waiting for an emergency delivery if the mother is at high risk of fitting.
The correct treatment of pre-eclampsia prevents eclampsia, and the prognosis is very good if detected early and treated correctly. In subsequent pregnancies, the risk of recurrence is 15%. Unfortunately there is no regime that will prevent preeclampsia or a recurrence, although low dose aspirin is being used experimentally for prevention in high risk mothers.