Eclampsia

Eclampsia is a hypertensive emergency of pregnancy defined by new-onset tonic-clonic, focal, or multifocal seizures (or unexplained altered mental status) in a pregnant or postpartum patient, in the absence of other causative etiologies such as epilepsy, intracranial hemorrhage, or drug use. [1-3] It is a leading cause of maternal mortality globally, with an incidence of 1.6–10 per 10,000 deliveries in developed countries and up to 151 per 10,000 in developing countries. [4] Critically, 20–38% of patients have no prior documented hypertension or proteinuria before the seizure. [3]

• Timing: Onset after 20 weeks' gestation; 50% antepartum, 50% intrapartum or postpartum (up to 6 weeks, most within 48 hours) [2-3]
• Prodromal symptoms (present in ~80%): Severe persistent headache (frontal/occipital), visual disturbances (scotomata, blurred vision, photophobia, flashing lights), altered cognition [2-3]
• Seizure characterization: Tonic-clonic most common; ask about duration, number of episodes, postictal state, tongue biting, incontinence
• Associated symptoms: Epigastric or RUQ pain, nausea/vomiting, facial/hand edema, decreased urine output, dyspnea [5-6]
• Important negatives: Prior seizure history, epilepsy, recent drug/substance use, head trauma, fever/infection

• Seizure activity in any pregnant or postpartum patient (up to 6 weeks)
• Severe hypertension ≥160/110 mm Hg [2][7]
• Persistent altered mental status or focal neurologic deficits post-seizure (consider intracranial hemorrhage, stroke, or cerebral venous thrombosis) [3]
• Signs of HELLP syndrome: RUQ pain, malaise, rapid clinical deterioration [2]
• Pulmonary edema, oliguria, or DIC [4]
• Recurrent seizures despite magnesium sulfate (consider alternative diagnoses) [3]
• Seizures occurring >48–72 hours postpartum or during magnesium sulfate infusion should raise suspicion for alternative etiologies [3]

• Magnesium sulfate — Drug of choice for seizure treatment and prevention of recurrence. Superior to phenytoin, diazepam, and lytic cocktail [3][8]
  • Loading dose: 4–6 g IV over 15–20 minutes
  • Maintenance: 1–2 g/hour IV infusion
  • If already on prophylactic magnesium: additional 2–4 g bolus after seizure [2]
  • IM alternative (resource-limited settings): 5 g into each buttock, then 5 g IM every 4 hours [9-10]
• Antihypertensives for severe HTN (≥160/110 mm Hg): IV labetalol, IV hydralazine, or oral immediate-release nifedipine (if no IV access) — initiate within 30–60 minutes [2][7]
• Contraindicated medications: ACE inhibitors, ARBs, direct renin inhibitors (teratogenic); avoid atenolol; use caution combining nifedipine with magnesium sulfate (risk of hypotension) [7]
• Magnesium toxicity monitoring: Loss of deep tendon reflexes (early sign), respiratory depression, apnea, cardiac arrest (severe) [2]
• Benzodiazepines (diazepam, midazolam, clonazepam) only if magnesium is contraindicated or unavailable, or for extreme agitation to facilitate IV access — use cautiously due to aspiration and respiratory depression risk [3]

• Not a primary management consideration in the acute setting
• Hydration: Judicious IV fluid management; avoid fluid overload given risk of pulmonary edema
• Long-term (postpartum): Heart-healthy diet, sodium moderation, and weight management given increased long-term cardiovascular risk [4][9]

• Neurologic: Headache, visual changes, altered mental status, seizure history, focal weakness
• GI: Epigastric/RUQ pain, nausea, vomiting (liver involvement, HELLP)
• Renal: Decreased urine output, dark urine, edema
• Pulmonary: Dyspnea, orthopnea (pulmonary edema)
• Hematologic: Easy bruising, bleeding (thrombocytopenia, DIC)
• OB: Vaginal bleeding (placental abruption), decreased fetal movement, contractions

• Collateral: Prenatal records (prior BP readings, proteinuria, labs), witnessed seizure details, medication compliance, substance use
• Family history: Preeclampsia/eclampsia in first-degree relatives increases risk [11]
• Social context: Access to prenatal care, social determinants of health; Black patients have disproportionately higher prevalence and complication rates [11]

• Nulliparity (strongest obstetric risk factor) [11-12]
• Prior preeclampsia or eclampsia [11]
• Chronic hypertension (up to 50% develop superimposed preeclampsia) [2]
• Pregestational diabetes (type 1 or type 2) [11]
• Chronic kidney disease, autoimmune disease (e.g., SLE, antiphospholipid syndrome) [11]
• Multifetal gestation [11]
• Obesity / high prepregnancy BMI [11]
• Maternal age ≥35 years [11]
• IVF conception [12]
• Inadequate prenatal care [4]

• Epilepsy — prior seizure history, normal BP, no proteinuria
• Intracranial hemorrhage (subarachnoid, intracerebral) — sudden severe headache, focal deficits; CT head to differentiate [3]
• Cerebral venous sinus thrombosis — headache, seizures, focal deficits; pregnancy is a risk factor
• Posterior reversible encephalopathy syndrome (PRES) — overlaps significantly with eclampsia; diagnosed by MRI showing vasogenic edema in posterior brain [3-4]
• Reversible cerebral vasoconstriction syndrome (RCVS) — thunderclap headache, may mimic eclampsia [3]
• Ischemic stroke [3]
• Thrombotic thrombocytopenic purpura (TTP) / Hemolytic uremic syndrome (HUS) — microangiopathic hemolytic anemia, thrombocytopenia
• Acute fatty liver of pregnancy — nausea, vomiting, jaundice, hypoglycemia, coagulopathy [2]
• Metabolic causes: Hypoglycemia, hyponatremia, hypocalcemia
• Drug-related seizures (cocaine, amphetamines, withdrawal)
• Meningitis/encephalitis — fever, meningismus

• Prior preeclampsia/eclampsia or HELLP syndrome
• Chronic hypertension, renal disease, diabetes
• Autoimmune conditions (SLE, antiphospholipid syndrome)
• Prior adverse pregnancy outcomes (IUGR, stillbirth, abruption)
• Seizure disorder or neurologic history
• Thrombophilia

• Vital signs: Hypertension (may be severe ≥160/110 mm Hg, but BP can be normal in up to 20–38% of cases); tachycardia; hypoxia (aspiration, pulmonary edema) [3]
• Neurologic: Mental status (postictal state, altered consciousness), clonus (≥3 beats is significant), hyperreflexia (3+ to 4+ DTRs), visual field deficits, tongue laceration [3]
• Fundoscopic: Papilledema, retinal vasospasm
• Abdominal: RUQ/epigastric tenderness (hepatic involvement), uterine tenderness (abruption), fundal height assessment
• Extremities: Edema (facial, hands — more concerning than dependent edema)
• Pulmonary: Crackles (pulmonary edema)
• Fetal assessment: Fetal heart tones, continuous fetal monitoring — expect prolonged decelerations during/after seizure [3]

• Head CT (non-contrast): Not routinely required after a typical eclamptic seizure, but indicated for atypical presentations — focal deficits, prolonged altered mental status, seizures >48 hours postpartum, seizures on magnesium, or failure to improve. Rules out intracranial hemorrhage. [1][4]
• Brain MRI: Gold standard for diagnosing PRES — shows vasogenic edema and T2/FLAIR hyperintensities in posterior cerebral regions. Most PRES findings resolve within 1–2 weeks. Routine MRI follow-up is unnecessary unless hemorrhage, infarction, or persistent neurologic deficits are present. [3-4]
• Obstetric ultrasound: Fetal assessment (growth, amniotic fluid, Doppler), placental evaluation (abruption)
• Chest X-ray: If concern for pulmonary edema or aspiration

• Continuous fetal monitoring: Essential — expect fetal heart rate decelerations during and after seizure; usually normalizes with maternal resuscitation [3]
• Angiogenic biomarkers: sFlt-1/PlGF ratio has high negative predictive value for ruling out preeclampsia but is not yet standard for eclampsia diagnosis [13]
• EEG: Not routinely indicated; consider if seizures are atypical or refractory to magnesium

• Obtain baseline ECG to evaluate for cardiac ischemia, arrhythmia, or electrolyte abnormalities (hypo/hypermagnesemia, hyperkalemia)
• Magnesium toxicity patterns: Prolonged PR interval, widened QRS, heart block at supratherapeutic levels
• Consider echocardiography if signs of heart failure or pulmonary edema

Eclampsia is a clinical diagnosis — new-onset seizures in a pregnant or postpartum patient after exclusion of other causes. [1-2] Key clinical pearls:

• Eclampsia does not follow a predictable linear progression from mild preeclampsia; it can present abruptly without prior hypertension or proteinuria in 20–38% of cases [3]
• 80% of cases are preceded by prodromal neurologic symptoms (headache, visual changes) [2]
• Complications include placental abruption, DIC, pulmonary edema, aspiration pneumonia, cardiopulmonary arrest, acute renal failure, and maternal death [4]
• Long-term sequelae include increased cardiovascular risk and cognitive difficulties (memory, concentration) [4]
• Permanent white matter loss on MRI documented in up to 25% of patients, though typically without significant neurologic deficits [3]

Immediate stabilization (ABCs)

• Call for help — activate OB and anesthesia
• Position in left lateral decubitus to prevent aspiration and optimize uteroplacental perfusion [3]
• Protect from injury (pad side rails, do not restrain)
• Supplemental oxygen, monitor SpO2
• Suction available; protect airway

Magnesium sulfate (first-line)

• 4–6 g IV loading dose over 15–20 minutes → 1–2 g/hour maintenance infusion [2][9-10]
• If already on magnesium prophylaxis: 2–4 g IV bolus [2]
• Continue for 24–48 hours postpartum (or 24 hours after last seizure)
• Monitor: respiratory rate (>12/min), urine output (>25–30 mL/hr), deep tendon reflexes, mental status [2]
• Antidote for toxicity: Calcium gluconate 1 g IV

Blood pressure control (if ≥160/110 mm Hg)

• IV labetalol: 20 mg, then 40 mg, then 80 mg every 10–20 minutes (max 300 mg)
• IV hydralazine: 5–10 mg every 20 minutes
• Oral nifedipine (immediate-release): 10–20 mg every 20–30 minutes (if no IV access) [2][7]
• Target: reduce BP to <160/110 mm Hg; avoid precipitous drops

Definitive treatment

• Delivery is the definitive treatment [1][4]
• Stabilize the mother first — maternal resuscitation typically normalizes fetal heart tracing [3]
• Do not rush to cesarean during the seizure; most seizures are self-limited (60–90 seconds) [3]
• Mode of delivery depends on gestational age, cervical status, and maternal/fetal condition
• Antenatal corticosteroids if <34 weeks and delivery can be safely delayed [2][9]

• All patients with eclampsia require ICU-level or high-acuity inpatient monitoring [1-2]
• Admission criteria: All eclampsia cases — no outpatient management
• Transfer criteria: If delivering facility lacks OB, anesthesia, NICU, or ICU capabilities, stabilize and transfer emergently [1]
• Specialist consultation: OB (emergent), MFM, anesthesia, neonatology; neurology if atypical features
• Postpartum monitoring: BP peaks on days 3–6 after delivery; continue monitoring with labs (platelets, creatinine, LFTs) at least twice weekly until normalizing [9]

• Postpartum BP monitoring: Home BP monitoring recommended; peak hypertension occurs days 3–6 postpartum [9]
• Magnesium sulfate: Continue 24–48 hours after delivery or last seizure
• Antihypertensives: May be needed for weeks postpartum; most agents are compatible with breastfeeding [9]
• Return precautions: Severe headache, visual changes, seizure recurrence, epigastric/RUQ pain, shortness of breath, decreased urine output, excessive edema
• Long-term counseling: Increased lifetime risk of cardiovascular disease (hypertension, ischemic heart disease, stroke), recurrence of preeclampsia in future pregnancies, and potential cognitive effects [4][9]
• Follow-up timing: OB visit within 3–7 days postpartum for BP check; comprehensive postpartum visit at 6 weeks with cardiovascular risk assessment [9]
• Aspirin prophylaxis (81 mg daily starting at 12 weeks) recommended in future pregnancies given high recurrence risk [13]

1. High Risk and Low Prevalence Diseases: Eclampsia. — Boushra M, Natesan SM, Koyfman A, Long B. The American Journal of Emergency Medicine. 2022.

2. Hypertensive Disorders of Pregnancy. — Farahi N, Oluyadi F, Dotson AB. American Family Physician. 2024.

3. Gestational Hypertension and Preeclampsia: ACOG Practice Bulletin, Number 222. — Committee on Practice Bulletins—Obstetrics Obstetrics and Gynecology. 2020.

4. Eclampsia in the 21st Century. — Fishel Bartal M, Sibai BM. American Journal of Obstetrics and Gynecology. 2022.

5. Pre-Eclampsia. — Chappell LC, Cluver CA, Kingdom J, Tong S. Lancet. 2021.

6. Preeclampsia. — National Library of Medicine (MedlinePlus) 2016.

7. Cardiovascular Considerations in Caring for Pregnant Patients: A Scientific Statement From the American Heart Association. — Mehta LS, Warnes CA, Bradley E, et al. Circulation. 2020.

8. Alternative Magnesium Sulphate Regimens for Women With Pre-Eclampsia and Eclampsia. — Diaz V, Long Q, Oladapo OT. The Cochrane Database of Systematic Reviews. 2023.

9. Preeclampsia. — Magee LA, Nicolaides KH, von Dadelszen P. The New England Journal of Medicine. 2022.

10. FDA Drug Label. — Updated date: 2026-01-09. Food and Drug Administration.

11. Screening for Hypertensive Disorders of Pregnancy: US Preventive Services Task Force Final Recommendation Statement. — US Preventive Services Task Force, Barry MJ, Nicholson WK, et al. The Journal of the American Medical Association. 2023.

12. Pregnancy and the Liver. — Rahim MN, Williamson C, Kametas NA, Heneghan MA. Lancet. 2025.

13. 2025 AHA/­ACC/­AANP/­AAPA/­ABC/­ACCP/­ACPM/­AGS/­AMA/­ASPC/­NMA/­PCNA/­SGIM Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/­American Heart Association Joint Committee on Clinical Practice Guidelines. — Jones DW, Ferdinand KC, Taler SJ, et al. Journal of the American College of Cardiology. 2025.