eMedicine Specialties > Obstetrics and Gynecology > Obstetrical Complications

Eclampsia: Treatment & Medication

Author: Michael G Ross, MD, MPH, Professor of Obstetrics and Gynecology, David Geffen School of Medicine, University of California at Los Angeles; Professor, Department of Community Health Sciences, University of California at Los Angeles School of Public Health; Chair, Department of Obstetrics and Gynecology, Harbor-UCLA Medical Center
Contributor Information and Disclosures

Updated: Apr 1, 2009

Treatment

Medical Care

Eclamptic convulsions are life-threatening emergencies and require the proper treatment to decrease maternal morbidity and mortality.  

• The first priority is to prevent maternal injury and to provide respiratory and cardiovascular support.
  • Supplemental oxygen should be administered
  • Place patient in the left lateral position. This positioning decreases the risk of aspiration and will help to improve uterine blood flow by relieving obstruction of the vena cava by the gravid uterus.
  • Protect patient against injury during the seizure by padding and raising guardrails, using a padded tongue blade between the teeth, and suctioning the oral secretions as needed.
• Establish intravenous access: After the seizure has ended, a 16- to 18-gauge intravenous line should be established for drawing specimens and administering fluids and medications. Intravenous fluids should be limited to isotonic solutions to replace urine output plus about 700 mL/d to replace insensible losses.
• Control of the seizure
  • No attempt to shorten or abolish the initial seizure is generally needed.
  • Magnesium sulfate is administered to prevent and treat subsequent seizures in women with eclampsia. Give intravenously as a loading dose of 4-6 g over 20 minutes followed by a maintenance dose of 1-2 g/h as a continuous intravenous infusion.
  • Recurrent seizures: About 10% of women with eclampsia will have an additional seizure after receiving magnesium sulfate. Another 2 g bolus of magnesium may be given in these cases. For the rare patient who continues to have seizure activity while receiving adequate magnesium therapy, seizures may be treated with sodium amobarbital, 250 mg intravenously over 3-5 minutes.⁵ More commonly, lorazepam (Ativan) 4 mg IV over 2-5 minutes (may repeat in 5-15 min to maximum of 8 mg in 12 hours or diazepam (Valium), 5-10 mg IV slowly (may be repeated every 15 min up to 30 mg) both as per protocol for status epilepticus.
• Control hypertension: Blood pressure should be assessed with the goal of maintaining diastolic blood pressure less than 110 mm Hg with administration of antihypertensive medications as needed (eg, hydralazine, labetalol).
• Monitoring
  • Regularly check neurologic status for signs of increased intracranial pressure or bleeding (eg, fundiscopic examination, cranial nerves)
  • Monitor fluid intake and urine output, maternal respiratory rate, and oxygenation, as indicated.
  • Continuously monitor fetal status.
  • Invasive monitoring: Pulmonary arterial pressure monitoring is rarely indicated but may be helpful in patients who have evidence of pulmonary edema or oliguria/anuria.
• Assessment for other coexisting medical conditions: Once the seizure is controlled and the patient has regained consciousness, the general medical condition should be assessed to identify any other causes for seizures.
• Induction of labor may be initiated when the patient is stable.
• Delivery (antepartum or intrapartum eclampsia)
  • Delivery is the treatment for eclampsia after the patient has been stabilized. No attempt should be made to deliver the infant either vaginally or by cesarean delivery until the acute phase of the seizure or coma has passed. The mode of delivery should be based on obstetric indications but should be chosen with an awareness of the fact that vaginal delivery is preferable from a maternal standpoint.
  • Adequate maternal pain relief for labor and delivery is vital and may be provided with either systemic opioids or epidural anesthesia.
  • In the absence of fetal malpresentation or fetal distress, oxytocin or prostaglandins may be initiated to induce labor.
  • Cesarean delivery may be considered in patients with an unfavorable cervix and a gestational age of 30 weeks or less, as induction under these circumstances may result in a prolonged intrapartum course and is frequently unsuccessful in avoiding cesarean section given the high rate of intrapartum complications.³
  • Intrapartum complications include the following:
    • Fetal growth retardation (30%)
    • Nonreassuring fetal heart rate patterns (30%)
    • Placental abruption (23%)
  • Irrespective of gestational age, a prolonged induction with clinically significant worsening of maternal cardiovascular, hematologic, renal, hepatic, and/or neural status is generally an indication for cesarean delivery when the anticipated delivery time is remote. 
• The highest maternal mortality rate associated with preeclampsia and eclampsia occurs in pregnancies 28 weeks’ gestation or less.⁷
• Fetal monitoring
  • Fetal heart rate and uterine contractions should be continuously monitored. Fetal bradycardia is common following the eclamptic seizure and has been reported to last from 30 seconds to 9 minutes. The interval from the onset of the seizure to the fall in the fetal heart rate is typically 5 minutes or less. Transitory fetal tachycardia may occur following the bradycardia.
  • After the initial bradycardia, during the recovery phase, the fetal heart rate tracing may reveal a loss of short- and long-term variability and the presence of late decelerations. These abnormalities are most likely due to the decrease in uterine blood flow caused by the intense vasospasm and uterine hyperactivity during the convulsion. If the fetal heart tracing does not improve following a seizure, further evaluation should be undertaken. Growth restricted and preterm fetuses may take longer to recover following a seizure. Placental abruption may be present if uterine hyperactivity remains and fetal bradycardia persists.

Surgical Care

• Cesarean delivery may be necessary for obstetric indications or deteriorating maternal condition.
• The patient should be stabilized with respect to seizures, oxygenation, and hemodynamic status before initiating cesarean delivery. Blood pressure should be controlled and coagulopathies monitored or corrected.  
• An anesthesiology consultation may be obtained. Early evaluation is recommended to assist with cardiopulmonary stabilization and prepare for a possible operative delivery or endotracheal intubation.
• For nonemergency cesarean delivery, epidural or combined techniques of regional anesthesia are preferred. Regional anesthesia is contraindicated in the presence of coagulopathy or severe thrombocytopenia (<50,000). General anesthesia in women with eclampsia increases the risk of aspiration and airway edema may make intubation difficult. It also can produce significant increases in systemic and cerebral pressures during intubation and extubation.
• The use of spinal anesthesia requires caution because of the possibility of total sympathetic blockade, resulting in maternal hypotension and uteroplacental insufficiency.

Consultations

• An experienced obstetrician or maternal-fetal medicine specialist may be consulted.
• Transport to a tertiary care site after stabilization may be in the best interest of the fetus or mother.
• In the event of premature delivery or fetal compromise, a pediatrician or neonatologist should be consulted.

Diet

Keep nothing by mouth (including medications) until the patient is medically stabilized or delivered as she is at risk of aspiration when postictal and may have recurrent seizures.

Activity

• Strict bedrest (Use thromboprophylaxis as indicated.)
• Maintain in lateral position to relieve the uterine pressure on the inferior vena cava and thereby improve uterine blood flow to the fetus and venous return to the mother.

Medication

Pharmacotherapy goals are to reduce morbidity, prevent complications, and correct eclampsia. The drug of choice to treat and prevent eclampsia is magnesium sulfate.⁸ Familiarity with second-line medications phenytoin and diazepam/lorazepam is required for cases in which magnesium sulfate may be contraindicated (eg, myasthenia gravis) or ineffective. Control of hypertension is essential to prevent further morbidity or possible mortality. The most commonly used antihypertensive agents are hydralazine, labetalol, and nifedipine. These vital medications are described below.

Anticonvulsants

Prevent seizure recurrence and terminate clinical and electrical seizure activity.

Magnesium sulfate

Several studies have revealed that magnesium sulfate is the drug of choice for treating eclamptic seizures. Magnesium sulfate is successful in controlling seizures in >95% of cases. The agent has physiologic advantages to the fetus by increasing uterine blood flow.
The mechanism of action of magnesium sulfate therapy is that it inhibits the release of acetylcholine at the motor endplate. In addition, magnesium has a direct effect on skeletal muscle by virtue of its competitive antagonistic effects with calcium.
Magnesium sulfate is excreted exclusively by the kidneys and has little antihypertensive effect. It is an effective anticonvulsant and helps prevent recurrent seizures and maintain uterine and fetal blood flow.
It can be administered both IV and IM. The intravenous route is preferred over the IM route because administration is more easily controlled and time to therapeutic levels is shorter. Intramuscular administration of magnesium sulfate tends to be more painful and less convenient. If IV access is unavailable, IM administration may be considered.
The goals of magnesium therapy are to terminate ongoing seizures and prevent further seizures. The patient should be evaluated approximately every 1 h to assure that deep tendon reflexes are present, respirations are at least 12 bpm, and urine output is at least 100 mL during the preceding 4 h. When using magnesium sulfate, close monitoring of the patient and fetus is necessary.
Magnesium therapy is usually continued for 12-24 h following delivery and may be stopped depending upon the clinical situation (eg, hypertension resolution, adequate urine output). Renally compromised patients should be monitored with magnesium levels, with adjustments made to facilitate levels at 6-8 mg/dL. Patients with increased urine output may need maintenance dose increased to 3 g/h to maintain therapeutic levels. Monitor patient for signs of worsening condition and magnesium toxicity.

Phenytoin (Dilantin)

Although phenytoin is not as effective as magnesium for prophylaxis or treatment of eclampsia, it can be safely and successfully used when magnesium is inappropriate, such as in women with myasthenia gravis or markedly compromised renal function.
Some benefits to using phenytoin are that it can be continued orally for several days until the risk of eclamptic seizures has subsided, it has established therapeutic levels that are easily tested, and no known neonatal adverse effects are associated with short-term usage. Nonetheless, phenytoin does have potential severe adverse effects that may be magnified by the rarity of its use in the obstetric setting. Cardiac monitoring is often required with IV loading.

Diazepam (Valium)

Freely crosses placenta and accumulates in fetal circulation with newborn levels 1-3 times maternal serum concentrations. Moreover, plasma half-life in newborn is increased due to decreased clearance and there are significant fetal CNS depressant effects. Nonetheless, diazepam (if not the shorter acting benzodiazepine lorazepam) may be necessary to treat recurrent seizure activity in patients already adequately treated with magnesium.
Should not be administered to stop or shorten the initial seizure, especially if IV access or the ability to rapidly intubate the patient is not readily available.

Lorazepam (Ativan)

Benzodiazepine indicated for treatment of status epilepticus and used for recurrent seizures in patients already receiving therapeutic magnesium. Lorazepam crosses placenta, achieving cord levels similar to maternal serum concentrations. Placental transfer is slower than that of diazepam and it is cleared less slowly in the neonate. For these reasons, it is commonly preferred over diazepam. Nonetheless, at high IV doses, lorazepam may also produce floppy infant syndrome (see diazepam for description).

Antihypertensives

Hypertension associated with eclampsia is often adequately controlled by stopping the seizure.

Antihypertensive medications are used to maintain diastolic blood pressure <110 mm Hg.

Antihypertensive therapy has 2 main goals: (1) reducing maternal morbidity and mortality associated with seizures, strokes, and pulmonary embolism, and (2) potentially reducing fetal morbidity and mortality secondary to intrauterine growth restriction, placental abruption, and infarcts.

Uterine hypoperfusion may result if blood pressure is lowered too quickly. Uterine vasculature is generally maximally vasodilated; thus a decrease in maternal systemic blood pressure tends to decrease uteroplacental perfusion.

Although total body water in patients with eclampsia is excessive, intravascular volume is contracted and women with eclampsia are very sensitive to further volume changes. Hypovolemia results in decreased uterine perfusion. Therefore, diuretics generally should be avoided in eclampsia, unless indicated for maternal symptoms (eg, pulmonary edema).

Drugs used most commonly for hypertension in pregnancy are hydralazine and labetalol. Nifedipine has also been used to control hypertension, but less commonly as it cannot be given intravenously.

Hydralazine (Apresoline)

Drug is a direct arteriolar vasodilator that causes a secondary baroreceptor-mediated sympathetic discharge resulting in tachycardia and increased cardiac output.
Hydralazine helps to maintain uterine blood flow and blunts the hypotensive response.
Hydralazine is metabolized in the liver.
Controls hypertension in up to 95% of patients with eclampsia.

Labetalol (Normodyne, Trandate)

Nonselective beta-blocker.
Available in IV and PO preparations. Used as an alternative to hydralazine in eclampsia. Uteroplacental blood flow appears to be unaffected by IV labetalol.

Nifedipine (Adalat, Procardia)

Produces calcium channel blockade, causing powerful arteriolar vasodilation.
Only available in PO form.

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