Preeclampsia, Eclampsia and HELLP Syndrome

Preeclampsia is new hypertension after 20 weeks of gestation, or up to 6 weeks postpartum. BP alone is not enough. It needs proteinuria or a severe feature. Eclampsia is the seizure version: a new seizure in the same window, with no other cause. HELLP syndrome (hemolysis, elevated liver enzymes, low platelet count) can show up alongside preeclampsia. The ACOG algorithms tell you to watch for it.

We still do not know the cause (per ISSHP 2021). What we do know is that several organs can be hit at once: brain, liver, kidneys, lungs and platelets. So management covers blood pressure, seizures, magnesium and organ checks.

• Gestational hypertension: SBP ≥140 or DBP ≥90 mm Hg after 20 weeks with normal BP before, persisting for 4 hours, with normal labs, no symptoms and no proteinuria.
• Preeclampsia: the same BP with proteinuria (urine protein/creatinine ratio ≥0.3 or dipstick ≥2+). Hypertension without proteinuria becomes preeclampsia with severe features when a lab abnormality or symptom is present (next bullet).
• Preeclampsia with severe features: SBP ≥160 or DBP ≥110 (confirm within 15 min), or BP 140–159 or 90–109 with any lab abnormality or symptom: platelets below 100 × 10⁹/L, AST or ALT at 2 times the upper limit, creatinine above 1.1 mg/dL or a doubling, pulmonary edema, unresponsive new headache, visual disturbance, or persistent RUQ or epigastric pain.
• Eclampsia: new tonic-clonic, focal or multifocal seizure with no other cause such as hypoglycemia or drug or alcohol withdrawal. The patient may or may not be hypertensive. It can occur up to 6 weeks postpartum.

Hypertension alone

At SBP 140–159 or DBP 90–109, the BP may be the only abnormal sign. Treat it as possible preeclampsia. Recheck the BP and ask about symptoms. Don't wave off a high reading just because the patient feels fine.

Preeclampsia with severe features

A reading of SBP ≥160 or DBP ≥110 that lasts 15 minutes needs an antihypertensive and magnesium. No symptoms required. BP of 140–159 or 90–109 is different. With a severe headache, blurred vision, or right upper quadrant or epigastric pain, it needs magnesium per NAEMSP 2025.

Eclampsia

A seizure, generalized or focal, in pregnancy or up to 6 weeks postpartum, with no other cause turning up. The BP may be normal. Don't let a normal number talk you out of it.

Red Flags

• SBP ≥160 or DBP ≥110 mm Hg that persists for 15 minutes
• Any seizure in pregnancy or up to 6 weeks postpartum with no other cause
• Shortness of breath or pulmonary edema
• Severe headache with hypertension: consider stroke per ACOG 2023
• Blurred vision, RUQ or epigastric pain
• Urine output below 100 mL every 4 hours while on magnesium: the premix label says to stop the infusion. Magnesium accumulates when output falls. The label's renal-dosing threshold of 0.5 mL/kg/hr sits in Special Populations.

Most of this workup happens in the hospital. In the field, the checks that change your treatment are BP, glucose, oxygenation and the magnesium checks.

• Hypoglycemia, drug or alcohol withdrawal: These are seizure causes that the eclampsia definition rules out. Check glucose and ask about substances before the label goes on.
• Stroke or intracranial hemorrhage: In pregnancy or postpartum, a severe headache with hypertension means a stroke check, per ACOG 2023. A focal deficit goes down the Acute Ischemic Stroke pathway.
• Chronic hypertension: High BP that was there before 20 weeks does not fit the new-onset pattern of preeclampsia. The ACOG algorithm requires a normal BP beforehand. Treatment for severe-range BP stays the same.

1. Position: a visibly pregnant patient goes in the recovery or left-lateral position. If she must be supine for airway or access, displace the uterus to the left per NAEMSP 2025.
2. Seizure care: protect from injury, do not restrain, clear the airway and suction. Record the start time and length of each seizure.
3. Oxygen and airway: give oxygen for SpO₂ ≤94% and assist ventilation as needed. Advanced airway (Paramedic/RN/CCT) per protocol.
4. Vital signs: Check BP at least every 15 minutes. A reading of 140–159/90–109 with headache, visual change or upper abdominal pain is the magnesium trigger for the ALS team.
5. Notify early: give the receiving facility the gestational age or days postpartum, seizure times and the BP trend.
6. Transport: to a hospital with obstetric services, or the most appropriate local or regional facility.

Doses vary by protocol; follow local protocols and medical direction. Both drugs start together when both are indicated. If only one can start, the problem decides it: an antihypertensive for severe-range BP, magnesium for a seizure, per NAEMSP 2025 and ACOG 2023. These medication steps belong to advanced-level clinicians. Where local scope allows, an AEMT may give them, because NAEMSP 2025 includes advanced EMTs.

• IV access: Get an IV if you're able. IO magnesium in eclampsia has no supporting data, so an IV failure means IM magnesium.
• Magnesium sulfate (Paramedic/RN/CCT): 4 g IV over 20 minutes, then 2 g/hr by pump. Hospital dosing per ACOG 2023 runs wider: 4–6 g over 20–30 min, then 1–2 g/hr. The 50% vial never goes in undiluted IV, and the label wants it at 20% or less before IV use. With severe renal impairment, oliguria or creatinine of 1 mg/dL or higher, you ask OB or medical direction and slow the rate. The label then says 1 g/hr, with no more than 20 g over 48 hours. Heart block or myocardial damage, diabetic coma and myasthenia gravis are the label contraindications (see Special Populations). No IV at all? 10 g IM, 5 g in each buttock. You may mix it with 1 mL of 2% lidocaine. Still no IV, then 5 g IM every 4 hours, per ACOG 2023. See Magnesium Sulfate
• Seizure lasting more than 5 minutes despite magnesium (Paramedic/RN/CCT): Consider another cause, and give a benzodiazepine per protocol: lorazepam 4 mg IV over 3–5 min, or diazepam 5–10 mg IV slowly. Midazolam 10 mg IM (adult dose) is the no-IV option. Magnesium stacks CNS and respiratory depression on top of a benzodiazepine, so be ready to ventilate. See Lorazepam, Diazepam
• Labetalol (Paramedic/RN/CCT): Start with 20 mg IV over 2 min for SBP ≥160 or DBP ≥110 that lasts 15 min. Still severe at 10 min? Give 40 mg, then 80 mg every 10 min, max 300 mg cumulative (or a 1–2 mg/min infusion). Avoid it in asthma or bradycardia. See Labetalol
• Hydralazine (Paramedic/RN/CCT): 5 mg IV or IM. Per the ACOG 2023 algorithm, it is 5–10 mg IV, then 10 mg IV every 20 min, max 20 mg cumulative. Give it 20 minutes to take effect. See Hydralazine
• Nifedipine immediate-release (Paramedic/RN/CCT): 10 mg by mouth, not sublingual, then 20 mg every 20 min if still severe, max 180 mg/day per NAEMSP 2025. This is your first pick with no IV access. With asthma or bradycardia, choose hydralazine or nifedipine. Watch for hypotension when it is combined with magnesium. The premix label warns of pulmonary edema and hypotension with nifedipine, though it was written for unapproved tocolytic use. ACOG 2023 says that if it is still severe after the third dose (10 mg, then 20 mg, then 20 mg), you convert to labetalol and get emergent MFM or critical-care consultation.
• BP target: Aim for SBP 130–150 and DBP 80–100 mm Hg per NAEMSP 2025 and ACOG 2023. Once you reach it, monitor per protocol. If BP returns to ≥160/110, repeat the same drug and dose that worked.
• Nitroglycerin is not a BP treatment here: NAEMSP 2025 found no evidence that it lowers BP in pregnant or postpartum patients. Don't reach for it to bring the number down.
• Airway (Paramedic/RN/CCT): Protect the airway through the seizure. If it persists after magnesium and a benzodiazepine, intubation falls to the ED or ICU. See Rapid Sequence Intubation
• Monitoring: Continuous ECG and SpO₂. BP at least every 15 minutes. Check reflexes and respiratory rate while on magnesium.

• Obstetric team: Get OB involved immediately. Delivery mode and timing depend on the obstetric circumstances, per ACOG 2023.
• Magnesium duration: Keep it running for at least 24–48 hours after the last seizure or after delivery, whichever is later, per ACOG 2023. The maximum is 30–40 g in 24 hours. Infusion beyond 5–7 days is not recommended (per the FDA label).
• Serum magnesium: Draw the first level 4 hours after starting, then every 4 hours. Therapeutic is 4.9–8.5 mg/dL. Above 9.6 mg/dL, stop. Restart once it falls below 8.4 mg/dL, per ACOG 2023.
• Magnesium toxicity: Keep calcium at the bedside. Calcium gluconate 10 mL of 10% (1 g) IV over 3 min, or calcium chloride 5 mL of 10% (500 mg) IV over 5–10 min, per ACOG 2023. Toxicity doses differ between sources. Follow protocol.
• Seizure that persists after magnesium and a benzodiazepine: fosphenytoin 20 mg PE/kg IV at 150 mg PE/min, or levetiracetam 60 mg/kg IV, max 4,500 mg per ACOG 2023. During a fosphenytoin infusion, you need continuous ECG, blood pressure and respiratory monitoring. The label warns of severe hypotension and arrhythmia with rapid infusion. Consider intubation with propofol, and consult neurology, anesthesia, critical care or maternal–fetal medicine. See Fosphenytoin and Levetiracetam
• Refractory severe-range BP: Labetalol infusion at 1–2 mg/min, or other agents per protocol. If BP stays at or above 160/110 despite these steps, get emergent MFM or critical-care input per ACOG 2023.
• Head CT: Order it for severe headache or any neurologic symptom, per ACOG 2023. A focal deficit goes down the stroke pathway.
• Pulmonary edema: ICU care per local protocol. In the ACOG definition, it is a severe feature.

• Destination: A hospital with obstetric services, or the most appropriate local or regional facility. Tell the receiving facility early, per NAEMSP 2025. Postpartum patients up to 6 weeks count too.
• Time: Under a local plan, the NAEMSP model asks for treatment within 30–60 minutes. Start on scene wherever the protocol lets you.
• In transit: Keep the magnesium on the pump at the programmed rate. Check BP at least every 15 minutes, reassess reflexes and respiratory rate, and give oxygen for SpO₂ ≤94%.
• Handoff: gestational age or days postpartum, last seizure time, every drug with its time, total magnesium given, the infusion rate, the BP trend and urine output. The magnesium clock runs at least 24–48 hours from the last seizure or delivery, per ACOG 2023.
• Equipment: infusion pump with premixed magnesium, the antihypertensives, a benzodiazepine, 2% lidocaine for IM mixing, calcium gluconate or calcium chloride for toxicity, and suction, per protocol.

• Pediatrics: Preeclampsia and eclampsia are pregnancy conditions, and pregnant adolescents are included. Adolescent magnesium and antihypertensive doses follow the adult regimens above. Those regimens are not weight-based (see Magnesium Sulfate). A child who is not pregnant and has a seizure follows the pediatric pathway: Weight-Based Dosing.
• Pregnancy: Magnesium is the first-line drug for eclampsia and for preeclampsia with severe features. For severe BP, the ACOG algorithms name labetalol, hydralazine and immediate-release nifedipine. Nifedipine is the one you reach for when there is no IV access. Continuous maternal magnesium beyond 5 to 7 days can cause fetal abnormalities (per the FDA label). That is why the duration is limited.
• Renal Impairment: At creatinine of 1 mg/dL or higher, maintenance magnesium needs adjusting per ACOG 2023. With severe renal impairment or urine output below 0.5 mL/kg/hr, the label gives a 4 g load and then 1 g/hr, with frequent magnesium levels. Do not exceed 20 g over 48 hours (label).
• Magnesium Contraindications: The label lists heart block or myocardial damage, diabetic coma and myasthenia gravis. Ask about myasthenia gravis. Check the ECG when protocol allows. In a seizing patient, treat per medical direction and bring in OB or critical care early.
• Hepatic Impairment: These sources do not establish a specific adjustment. Track liver injury with AST and ALT.
• Asthma or Bradycardia: Avoid labetalol. Choose hydralazine or nifedipine, per NAEMSP 2025 and ACOG 2023.

• Error: Swapping grams for mL of the 50% vial. Remember that 4 g is 8 mL of 50%. Go premixed on a pump. A second set of eyes checks dose and rate when you start and at every bag change.
• Error: Holding severe-range treatment for labs or a repeat BP. Reconfirm the reading inside 15 minutes, then treat per ACOG 2023.
• Error: Reaching for nitroglycerin to bring BP down in pregnancy or postpartum. NAEMSP 2025 found no evidence that it lowers BP.
• Error: Giving labetalol to a patient with asthma or bradycardia. It is a beta-blocker, so bronchospasm and an already slow heart can both get worse. Hydralazine or nifedipine instead, per NAEMSP 2025.
• Error: Doses stacking on each other. Count labetalol boluses against 300 mg as you go, and recheck at 10 minutes. Hydralazine waits 20 minutes between doses.
• Error: A benzodiazepine as the first move for an eclamptic seizure. Magnesium leads. The benzodiazepine comes next when the seizure runs past 5 minutes despite magnesium, per NAEMSP 2025.
• Error: Missing toxicity from magnesium: lost reflexes, respiratory rate below 16/min or falling urine output. Calcium should be close at hand during the infusion, per ACOG 2023.
• Error: Forgetting to ask about pregnancy. In a woman of reproductive age with a seizure, ask about pregnancy and about any delivery in the last 6 weeks (per the ACOG 2023 eclampsia algorithm).