What are the management options for pre-eclampsia?

Management of Pre-eclampsia

Delivery is the only definitive cure for pre-eclampsia, but immediate management focuses on preventing maternal cerebral hemorrhage and eclamptic seizures through aggressive blood pressure control and magnesium sulfate administration, followed by carefully timed delivery based on gestational age and disease severity. 1, 2

Initial Assessment and Hospitalization

All women with newly diagnosed pre-eclampsia require immediate hospitalization to confirm diagnosis, assess severity, and monitor disease progression. 1, 3

Key diagnostic criteria include:

• New-onset hypertension (≥140/90 mmHg) after 20 weeks of gestation 1
• Plus proteinuria (>0.3 g/24h or albumin-to-creatinine ratio ≥30 mg/mmol) OR evidence of end-organ damage 4, 1
• End-organ damage includes: renal dysfunction (elevated creatinine), liver involvement (elevated transaminases), neurological symptoms (severe headache, visual disturbances), hematological complications (thrombocytopenia), or uteroplacental dysfunction (fetal growth restriction) 4, 5

Immediate maternal monitoring requirements:

• Blood pressure every 4 hours (more frequently if severe features present) 1, 3
• Continuous assessment for clonus and neurological symptoms 1
• Oxygen saturation monitoring (maternal early warning if <95%) 2
• Hourly urine output via Foley catheter with target ≥100 mL/4 hours or >35 mL/hour 2, 6
• Deep tendon reflexes before each magnesium dose to monitor for toxicity 2, 6

Laboratory monitoring at least twice weekly (more frequently with clinical deterioration):

• Complete blood count with platelets 1, 3
• Liver enzymes (AST, ALT) 1, 3
• Serum creatinine and uric acid 1, 3
• Peripheral blood smear if HELLP syndrome suspected 2

Initial fetal assessment:

• Ultrasound with fetal biometry, amniotic fluid volume, and umbilical artery Doppler 1, 3
• Repeat ultrasound every 2 weeks if initial assessment normal, more frequently if fetal growth restriction present 2, 3
• Continuous fetal heart rate monitoring for severe pre-eclampsia 3

Blood Pressure Management

Severe Hypertension (≥160/110 mmHg)

Severe hypertension requires urgent treatment within 15 minutes to prevent maternal cerebral hemorrhage while maintaining uteroplacental perfusion. 1, 3

Target blood pressure: Systolic 110-140 mmHg and diastolic 85 mmHg (or at minimum <160/105 mmHg). 1, 2, 3

First-line IV antihypertensive options:

• IV labetalol (preferred first-line agent): 20 mg IV bolus, then 40 mg after 10 minutes if needed, followed by 80 mg every 10 minutes to maximum total dose of 220 mg 4, 1, 2

• Oral nifedipine: 10 mg orally, repeat every 20 minutes to maximum 30 mg 1

  • Critical warning: Avoid sublingual or rapid IV administration of calcium channel blockers as this causes precipitous blood pressure drops leading to myocardial infarction or fetal distress 1
  • Never combine calcium channel blockers with IV magnesium sulfate due to risk of myocardial depression 1

• IV hydralazine: Alternative option but found inferior to other agents 4

• IV nitroglycerin (glyceryl trinitrate): Drug of choice for pulmonary edema, starting at 5 mcg/min, gradually increased every 3-5 minutes to maximum 100 mcg/min 2

• Sodium nitroprusside: Only as last resort for extreme emergencies due to risk of fetal cyanide poisoning 2

Absolutely contraindicated medications:

• ACE inhibitors, ARBs, and direct renin inhibitors are absolutely contraindicated during second and third trimesters due to severe fetotoxicity and renal dysgenesis 4, 1, 2
• Diuretics are contraindicated as they further reduce plasma volume 1, 3

Non-Severe Hypertension (≥140/90 mmHg)

For non-severe hypertension, initiate oral antihypertensives aiming for target diastolic BP of 85 mmHg and systolic BP between 110-140 mmHg. 1

Oral antihypertensive options:

• Labetalol 7
• Nifedipine 7
• Methyldopa 7

Magnesium Sulfate for Seizure Prophylaxis

Magnesium sulfate must be administered immediately to all women with severe pre-eclampsia or those with severe hypertension (≥160/110 mmHg) to prevent eclamptic seizures. 1, 2, 3

Dosing regimen for pre-eclampsia/eclampsia: 6

• Loading dose: 4-5 g IV over 5 minutes (diluted in 250 mL of 5% dextrose or 0.9% sodium chloride) 2, 6
• Maintenance dose: 1-2 g/hour continuous IV infusion 2, 6
• Alternative IM dosing: Simultaneously with IV loading dose, give up to 10 g IM (5 g or 10 mL of undiluted 50% solution in each buttock), then 4-5 g IM into alternate buttocks every 4 hours as needed 6
• Continue for 24 hours postpartum 1, 6

Critical monitoring for magnesium toxicity: 6

• Patellar reflex (knee jerk) must be present before each dose—if absent, hold magnesium until reflexes return 6
• Respiratory rate ≥16 breaths/minute 6
• Urine output ≥100 mL/4 hours 6
• Therapeutic serum magnesium levels: 3-6 mg/100 mL (2.5-5 mEq/L) for seizure control 6
• Deep tendon reflexes diminish when magnesium exceeds 4 mEq/L 6
• Reflexes may be absent at 10 mEq/L where respiratory paralysis is a potential hazard 6

Have injectable calcium salt immediately available to counteract magnesium toxicity. 6

Critical warning: Continuous maternal administration of magnesium sulfate beyond 5-7 days can cause fetal abnormalities including hypocalcemia, skeletal demineralization, and osteopenia. 6

Fluid Management

Strictly limit total fluid intake to 60-80 mL/hour to prevent pulmonary edema. 1, 3

• Aim for euvolemia—avoid "running dry" as this increases risk of acute kidney injury 1
• Plasma volume expansion is not recommended routinely 2
• Diuretics are contraindicated as they further reduce plasma volume 1, 3

Timing of Delivery

Delivery is the only definitive treatment for pre-eclampsia. 4, 1

Gestational Age ≥37 Weeks

Deliver immediately after maternal stabilization. 2, 3

• Induction of labor is associated with improved maternal outcome 2
• Vaginal delivery is preferred unless cesarean indicated for obstetric reasons 2

Gestational Age 34-37 Weeks

• Deliver at 37 weeks for pre-eclampsia without severe features 3
• Expectant conservative management appropriate if maternal and fetal status stable 2
• Deliver if any maternal or fetal deterioration occurs 2

Gestational Age <34 Weeks

• Administer corticosteroids for 48 hours to accelerate fetal lung maturation 4, 1, 3
• Conservative expectant management at a center with Maternal-Fetal Medicine expertise 2
• Close maternal and fetal surveillance essential 4

Gestational Age <24 Weeks

Expectant management associated with high maternal morbidity with limited perinatal benefit—counsel regarding pregnancy termination. 2

Absolute Indications for Immediate Delivery (Any Gestational Age)

Deliver immediately if any of the following develop: 4, 1, 2

• Repeated episodes of severe hypertension despite treatment with 3 classes of antihypertensives in appropriate doses 1, 2
• Progressive thrombocytopenia or progressively abnormal liver/renal function tests 2
• Pulmonary edema 2
• Severe intractable headache, repeated visual scotomata, or convulsions 2
• Placental abruption 1, 2
• Non-reassuring fetal status 1, 2
• Maternal pulse oximetry deterioration 2
• Laboratory evidence of end-organ dysfunction 4
• Fetal distress 4

Postpartum Management

Close monitoring must continue for at least 72 hours postpartum as eclampsia can still develop. 1, 3

• Monitor blood pressure at least every 4 hours while awake 1, 3
• Continue magnesium sulfate for 24 hours postpartum 1, 3
• Continue antihypertensives and taper slowly after days 3-6 postpartum 1

Prevention for Future Pregnancies

For women with high-risk factors, initiate low-dose aspirin (75-162 mg/day) before 16 weeks' gestation (ideally before 20 weeks). 1, 3, 8

High-risk factors include: 3

• History of pre-eclampsia
• Chronic hypertension
• Type 1 or 2 diabetes
• Renal disease
• Autoimmune disease
• Multifetal gestation

Supplemental calcium (1.2-2.5 g/day) if dietary intake likely low (<600 mg/day). 1

Long-Term Cardiovascular Risk Counseling

Women with history of pre-eclampsia have significantly increased lifetime risk of cardiovascular disease, stroke, venous thromboembolism, and diabetes. 1, 3, 9, 8

• Risk of recurrent pre-eclampsia in future pregnancies approximately 15%, with additional 15% risk of gestational hypertension 3
• Regular blood pressure monitoring by primary care physician recommended 3
• Pregnancy serves as a window for future cardiovascular health 9

Critical Pitfalls to Avoid

• Do not attempt to diagnose "mild versus severe" pre-eclampsia clinically—all cases may become emergencies rapidly 2
• Do not use serum uric acid or level of proteinuria as indication for delivery 2
• Do not reduce antihypertensives if diastolic BP falls <80 mmHg 2
• Never combine calcium channel blockers with IV magnesium sulfate 1
• Do not continue magnesium sulfate beyond 5-7 days due to fetal toxicity 6
• Avoid sublingual nifedipine due to risk of precipitous blood pressure drops 1