What is the recommended acute management of eclampsia in a pregnant or postpartum woman after 20 weeks gestation presenting with seizures?

Acute Management of Eclampsia After 20 Weeks Gestation

Immediately administer intravenous magnesium sulfate as the first-line anticonvulsant and initiate aggressive blood pressure control if systolic BP ≥160 mmHg or diastolic BP ≥110 mmHg, while simultaneously securing the airway and preparing for delivery after maternal stabilization. 1, 2, 3

Immediate Seizure Management

Acute Stabilization During Convulsion

• Ensure airway patency, adequate breathing, and circulation while protecting the patient from physical injury during the seizure 4, 3
• Position the patient on her left side to prevent aspiration and optimize uteroplacental blood flow 4
• Administer supplemental oxygen to maintain maternal oxygen saturation >90% and ensure adequate fetal oxygenation 1, 4

Magnesium Sulfate Administration

Magnesium sulfate is the definitive first-line anticonvulsant for eclampsia, superior to phenytoin or diazepam in preventing recurrent seizures. 1, 5, 6

• Loading dose: 4-5 g IV over 5 minutes (diluted in 250 mL of 5% dextrose or 0.9% normal saline) 1, 2
• Maintenance infusion: 1-2 g/hour continuous IV infusion 1, 2
• Alternative regimen: If IV access is delayed, administer 10 g IM (5 g in each buttock) simultaneously with the 4-5 g IV loading dose 2
• Continue for 24 hours after delivery to cover the high-risk postpartum period 1, 7

Magnesium Sulfate Monitoring Protocol

Critical safety monitoring is mandatory during magnesium infusion to prevent toxicity: 1, 2

• Maintain urine output ≥30 mL/hour (≥100 mL per 4 hours) using a Foley catheter 1
• Check patellar reflexes before each dose; absent reflexes indicate impending toxicity 1, 2
• Monitor respiratory rate continuously; hold magnesium if respirations <12 breaths/minute 1
• Keep 10% calcium gluconate (1 g or 10 mL) at bedside as the antidote for magnesium toxicity 1
• Target therapeutic magnesium level: 4-7 mEq/L (6 mg/100 mL optimal for seizure control) 2, 6

Blood Pressure Management

Severe Hypertension Threshold

If BP remains ≥160/110 mmHg for more than 15 minutes, initiate immediate IV antihypertensive therapy to prevent maternal cerebral hemorrhage. 1, 8

First-Line Antihypertensive Regimens

Labetalol IV (preferred in most settings): 1, 3

• 20 mg IV bolus over 2 minutes
• If inadequate response after 10 minutes: 40 mg IV
• If still inadequate after another 10 minutes: 80 mg IV
• Maximum cumulative dose: 220 mg

Hydralazine IV (alternative): 1, 5, 9

• 5-10 mg IV bolus every 20 minutes
• Repeat until BP controlled

Immediate-release nifedipine (oral alternative): 3

• 10 mg orally, repeat every 20-30 minutes if needed
• CRITICAL PITFALL: Do NOT combine short-acting nifedipine with magnesium sulfate due to risk of severe hypotension and myocardial depression 1

Target Blood Pressure

• Goal systolic BP: 110-140 mmHg 1
• Goal diastolic BP: approximately 85 mmHg (minimum <105 mmHg) 1

Laboratory and Fetal Assessment

Urgent Maternal Laboratory Panel

Obtain immediately to assess for severe features and complications: 1, 8

• Complete blood count with platelet count (thrombocytopenia <100 × 10⁹/L indicates severity)
• Comprehensive metabolic panel including AST, ALT (≥2× upper limit indicates hepatic dysfunction)
• Serum creatinine (>1.1 mg/dL indicates renal dysfunction)
• Urinalysis for proteinuria quantification

Fetal Monitoring

• Initiate continuous electronic fetal heart rate monitoring during and after seizure activity 1
• Obtain obstetric ultrasound to confirm fetal viability, gestational age, and assess for placental abruption 1

Delivery Planning

Indications for Immediate Delivery

Delivery is the definitive treatment for eclampsia and should proceed after maternal stabilization. 1, 6, 3

Absolute indications for immediate delivery (regardless of gestational age): 1

• Recurrent eclamptic seizures despite magnesium sulfate therapy
• Uncontrolled hypertension despite ≥3 antihypertensive drug classes
• Progressive thrombocytopenia or HELLP syndrome
• Worsening hepatic or renal function
• Pulmonary edema
• Non-reassuring fetal status
• Placental abruption

Timing Considerations

• At term (≥37 weeks): Proceed with delivery after maternal stabilization 6, 3
• Preterm (<37 weeks): Delivery timing depends on maternal stability, severity of eclampsia, and fetal status; most require delivery within 24-48 hours 6
• Postpartum eclampsia: Continue aggressive management; eclampsia can occur up to 6 weeks postpartum, with increasing cases beyond 48 hours after delivery 7, 6

Critical Medication Pitfalls

Absolute contraindications in pregnancy: 1

• ACE inhibitors, angiotensin-II receptor blockers, and direct renin inhibitors are teratogenic and strictly prohibited
• Routine diuretics should be avoided; furosemide is reserved ONLY for pulmonary edema

Avoid NSAIDs for postpartum analgesia, especially with renal dysfunction, acute kidney injury, or placental abruption 7

Do not use magnesium sulfate beyond 5-7 days due to risk of fetal skeletal demineralization, osteopenia, and neonatal fractures 2

Transfer and System-Level Care

Transfer any pregnant woman with eclamptic seizures to a facility with intensive care unit capabilities and maternal-fetal medicine expertise if not immediately available. 1 Eclampsia requires multidisciplinary care including obstetrics, anesthesia, and critical care medicine 4, 3