Preeclampsia

Preeclampsia is a disorder affecting some 5 to 8 percent of pregnant women. Also known as toxemia, it usually occurs in the third trimester of pregnancy and is characterized by increased blood pressure and protein in the urine as well as the abnormal function of many vital organs that can lead to a wide variety of other signs and symptoms. If severe, the disorder can evolve to eclampsia, which is distinguished by seizures and/or coma, which occurs in about 1/100 women with preeclampsia.

Types

Preeclampsia can be mild or severe.

Mild preeclampsia is defined ^{[1] [2]}as:

• blood pressure of 140 mm Hg systolic or higher, or 90 mm Hg diastolic or higher that occurs after 20 weeks of gestation in a woman with previously normal blood pressure
• proteinuria, (protein in the urine) defined as urinary excretion of 0.3 g protein or higher in a 24-hour urine specimen

Severe preeclampsia is diagnosed if one or more of the following criteria are present: • Blood pressure of 160 mm Hg systolic or higher, or 110 mm Hg diastolic or higher on two occasions at least 6 hours apart while the patient is on bed rest
• Proteinuria (protein in the urine) of 5 g or higher in a 24-hour urine specimen or 3+ or greater on two random urine samples collected at least 4 hours apart
• Oliguria (decrease in the production of urine) of less than 500 mL in 24 hours • Brain or visual disturbances
• Fluid accumulation in the lungs (pulmonary edema) or cyanosis (blue coloring of the skin due to a decrease of oxygen in the blood)
• Stomach or right upper-quadrant pain
• Impaired liver function
• Thrombocytopenia (low blood platelet count)
• Fetal growth restriction

Often thought of as a disease of the first pregnancy, it can occur in subsequent pregnancies. Fortunately, it is completely reversible with the delivery of the fetus. Preeclampsia may have a genetic component. It is more common if a sister has had preeclampsia, and if either parent is themselves the result of a preeclamptic pregnancy.

Signs and Symptoms

Signs of preeclampsia usually come before the symptoms. The most common sequence is increased blood pressure followed by protein in the urine.^[3]

Symptoms

Most women with early preeclampsia have no symptoms. This is the main reason for frequent doctor’s visits in late pregnancy. In most cases, signs such as increased blood pressure and protein in the urine come before overt symptoms. Headache is usually the first symptom, and is generally not relieved by standard medications like acetaminophen. Pain in the right upper central region of the abdomen may indicate liver problems. Visual symptoms such as flashing lights (scotomata), or even blindness can indicate swelling of the retina. Late signs of severe disease can include congestive heart failure, fetal growth restriction (poor fetal growth), and placental abruption (when the placenta separates from the uterus). Generalized swelling, particularly of the hands, feet and face can also be present.

Causes

The cause of preeclampsia is unknown.

Diagnosis

The diagnosis is clinical, made by the physician based on the patient’s signs and symptoms. There is no test for preeclampsia. (see types above)

Treatment

The only definitive treatment of preeclampsia is delivery of the fetus. The exact timing on the decision to deliver depends on gestational age of the fetus and the severity of disease. Severe disease near the end of the pregnancy is always treated with delivery, whereas a mild case of preeclampsia earlier in the pregnancy can be managed by the physician, who will closely monitor the patient’s blood pressure and other symptoms. Even in cases of severe disease earlier in the pregnancy, it may be appropriate to delay delivery to allow administration of corticosteroids to enhance fetal maturation. In general, this treatment should be done in experienced medical centers with intense maternal and fetal monitoring.

The mainstay treatment of preeclampsia during pregnancy is magnesium sulfate for the prevention of seizures. ^[4]

Magnesium sulphate has minimal effect on the mother’s blood pressure and so other medications may be necessary to control blood pressure before and during labor. It is best to avoid calcium channel blockers (e.g., nifedipine) as they may speed up magnesium activity. Other choices include hydralazine, amlodipine, and nitroglycerine.

Women receiving magnesium therapy for preeclampsia require close monitoring of intake fluids and output of urine.

Research

Women who had preeclampsia or eclampsia are more likely to suffer cardiac disease later in life, a risk factor often not appreciated by internists who may not tend to pay particular attention to pregnancy history. Several researchers^[5] learned that women who had eclampsia in subsequent pregnancies were two to five times more likely to die of cardiac disease than women who did not have eclampsia. Researchers also found that women were more likely to develop chronic hypertension later in life if they had recurrent preeclampsia during pregnancy.^[6]
These studies are the basis for a statement by The National High Blood Pressure Education Program’s Working Group on High Blood Pressure During Pregnancy that asserts that recurrent high blood pressure in pregnancy, preeclampsia in a woman who has had more than one pregnancy, and early-onset disease in any pregnancy may all be a sign of increased future health risks.^[7]
Funai and colleagues described excess long-term mortality in women with prior preeclampsia, mainly due to a three-fold increase in deaths as a result of cardiovascular disease.^[8]
Women who have had preeclampsia should make sure that their physicians are aware that they have had this condition. Maintaining a healthy weight, exercising regularly, quitting smoking and controlling high blood pressure will go a long way toward easing the effects of preeclampsia on long-term health.

References

1. ↑ Chesley L. Hypertensive Disorders in Pregnancy. New York: Appleton-Century-Crofts; 1978.
2. ↑ Dieckman W. The Toxemias of Pregnancy, 2nd ed. St Louis: CV Mosby; 1952.
3. ↑ Chesley L. Hypertensive Disorders in Pregnancy. New York: Appleton-Century-Crofts; 1978.
4. ↑ Lucas MJ, Leveno KJ, Cunningham FG. A comparison of magnesium sulfate with phenytoin for the prevention of eclampsia. N Engl J Med 1995;333:201-5.
5. ↑ Chesley SC, Annitto JE, Cosgrove RA. The remote prognosis of eclamptic women. Sixth periodic report. Am J Obstet Gynecol 1976;124:446-59.
6. ↑ Sibai BM, el-Nazer A, Gonzalez-Ruiz A. Severe preeclampsia-eclampsia in young primigravid women: subsequent pregnancy outcome and remote prognosis. Am J Obstet Gynecol 1986;155:1011-6.
7. ↑ Gifford R, August P, Cunningham G, et al. The national high blood pressure education program working group on high blood pressure in pregnancy. Bethesda: National Institutes of Health and National Heart, Lung and Blood Institute; 2000.
8. ↑ Funai EF, Friedlander Y, Paltiel O, et al. Long-term mortality after preeclampsia. Epidemiology 2005;16:206-15.