preeclampsia /prē′iklamp″sē·ə/ [L, prae + Gk, ek, out, lampein, to flash] , an abnormal condition of pregnancy characterized by the onset of acute hypertension after the 24th week of gestation. The classic triad of preeclampsia is hypertension, proteinuria, and edema. The cause of the disease remains unknown despite 100 years of research by thousands of investigators. It occurs in 5% to 7% of pregnancies, most often in primigravidas, and is more common in some areas of the world than others. The incidence is particularly high in the southeastern part of the United States. The incidence increases with increasing gestational age, and it is more common in cases of multiple gestation, hydatidiform mole, or hydramnios. A typical lesion in the kidneys, glomeruloendotheliosis, is pathognomonic. Termination of the pregnancy results in resolution of the signs and symptoms of the disease and in healing of the renal lesion. Preeclampsia is classified as mild or severe. Mild preeclampsia is diagnosed if one or more of the following signs develop after the 24th week of gestation: systolic blood pressure of 140 mm Hg or more or a rise of 30 mm Hg or more above the woman’s usual systolic blood pressure; diastolic blood pressure of 90 mm Hg or more or a rise of 15 mm Hg or more above the woman’s usual diastolic blood pressure; proteinuria; and edema. Severe preeclampsia is diagnosed if one or more of the following is present: systolic blood pressure of 160 mm Hg or more or a diastolic blood pressure of 110 mm Hg or more on two occasions 6 hours apart with the woman at bed rest; proteinuria of 5 g or more in 24 hours; oliguria of less than 400 mL in 24 hours; ocular or cerebrovascular disorders; and cyanosis or pulmonary edema. Preeclampsia commonly causes abnormal metabolic function, including negative nitrogen balance, increased central nervous system irritability, hyperactive reflexes, compromised renal function, hemoconcentration, and alterations of fluid and electrolyte balance. Complications include premature separation of the placenta, hypofibrinogenemia, hemolysis, cerebral hemorrhage, ophthalmological damage, pulmonary edema, hepatocellular changes, fetal malnutrition, and lowered birth weight. The most serious complication is eclampsia, which can result in maternal and fetal death. Healthy living conditions, including a diet high in protein, calories, and essential nutritional elements, and rest and exercise are associated with a decreased incidence of preeclampsia. Treatment includes rest, sedation, magnesium sulfate, and antihypertensives. Ultimately, if eclampsia threatens, delivery by induction of labor or cesarean section may be necessary. Formerly called toxemia of pregnancy. See also eclampsia.
