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For further information, see CMDT Part 19-12: Preeclampsia-Eclampsia

Key Features

Essentials of Diagnosis

  • Preeclampsia

    • Blood pressure of ≥ 140 mm Hg systolic or ≥ 90 mm Hg diastolic after 20 weeks gestation

    • Proteinuria of ≥ 0.3 g in 24 h

  • Preeclampsia with severe features (one or more of below)

    • Blood pressure of ≥ 160 mm Hg systolic or ≥ 110 mm Hg diastolic

    • Progressive kidney injury

    • Oliguria of < 500 mL in 24 h

    • Thrombocytopenia

    • Hemolysis elevated liver enzymes low platelets (HELLP)

    • Pulmonary edema

    • Vision changes or headache

    • When hypertension is present with severe features of preeclampsia, seizure prophylaxis could be beneficial

  • Eclampsia

    • Seizures in a patient with evidence of preeclampsia

General Considerations

  • Cause is unknown, but it is likely a multifactorial, two-stage process

    • The first stage: probable disturbance in placental implantation involving the spiral arteries very early in gestation; the abnormal placental perfusion that results leads to the formation of noxious free radicals

    • The second stage: excessive inflammation causing endothelial damage, vasospasm, and finally clinical signs and symptoms

  • An immunologic component has been proposed, citing the increased incidence in primigravidas

  • This entire process is likely enhanced by environmental factors, genetic predisposition, and preexisting maternal disease

  • Can occur any time after 20 weeks' gestation and up to 6 weeks postpartum

  • The only cure is delivery of the fetus and placenta

  • Uncontrolled eclampsia is a significant cause of maternal death

  • Preeclampsia progresses to eclampsia in 5% of women


  • Occurs in 7% of pregnant women in the United States

  • Higher incidence in primiparas

  • Other risk factors

    • Multifetal gestations

    • Preeclampsia in a previous pregnancy

    • Chronic hypertension

    • Pregestational diabetes

    • Gestational diabetes

    • Thrombophilia

    • Kidney disease

    • Systemic lupus erythematosus

    • Pre-pregnancy BMI above 30

    • Antiphospholipid antibody syndrome

    • Maternal age 35 years or older

    • Assisted reproductive technology

    • Obstructive sleep apnea

Clinical Findings

Symptoms and Signs

  • See Table 19–3

  • Preeclampsia without severe features

    • Patients usually have few complaints

    • Diastolic blood pressure < 110 mm Hg

    • Edema may be present

    • Platelet count > 100,000/mcL

    • Antepartum fetal testing is reassuring

    • CNS irritability is minimal

    • Epigastric pain is not present

    • Liver enzymes are not elevated

  • Preeclampsia with severe features

    • Patients may complain of headache and changes in vision

    • Blood pressure often ≥ 160/110 mm Hg

    • Thrombocytopenia (platelet counts < 100,000/mcL) may be present and progress to disseminated intravascular coagulation

    • Severe epigastric pain may be present from hepatic subcapsular hemorrhage with significant stretch or rupture of the liver capsule

    • HELLP syndrome is a form of severe preeclampsia

  • Severity can be assessed with reference to the six sites where disease has its effects

    • CNS

    • Kidneys

    • Liver

    • Hematologic system

    • Vascular system

    • Fetal placental unit

Table 19–3.Indicators of mild, moderate, and severe preeclampsia-eclampsia.

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