What is the management of preeclampsia in pregnant women?

Management of Preeclampsia

The management of preeclampsia requires urgent treatment of severe hypertension (≥160/110 mmHg) with oral nifedipine or intravenous labetalol or hydralazine, magnesium sulfate for seizure prophylaxis in severe cases, and delivery at 37 weeks' gestation or earlier if maternal or fetal complications develop. 1

Diagnosis and Initial Assessment

• Preeclampsia is diagnosed by hypertension (BP ≥140/90 mmHg) after 20 weeks gestation with proteinuria (≥30 mg/mmol protein/creatinine ratio) 1
• Initial assessment should include:
  • Blood pressure monitoring
  • Proteinuria assessment
  • Clinical assessment including clonus
  • Laboratory tests: hemoglobin, platelet count, liver enzymes, renal function, and uric acid
  • Fetal assessment with ultrasound 1

Antihypertensive Management

Severe Hypertension (≥160/110 mmHg)

• Requires urgent treatment in a monitored setting with:
  • Oral nifedipine, OR
  • IV labetalol (10-20 mg initially, then 20-80 mg every 10-30 minutes), OR
  • IV hydralazine (5-10 mg every 15-30 minutes) 2, 1

Mild-Moderate Hypertension (≥140/90 mmHg)

• Target diastolic BP of 85 mmHg (systolic 110-140 mmHg)
• First-line oral agents:
  • Methyldopa
  • Labetalol
  • Oxprenolol
  • Nifedipine
• Second-line agents: hydralazine and prazosin
• Reduce or cease antihypertensives if diastolic BP falls <80 mmHg 2, 1

Magnesium Sulfate Therapy

• Indicated for women with preeclampsia who have:

  • Proteinuria and severe hypertension, OR
  • Hypertension with neurological signs/symptoms 2

• Dosing regimen:

  • Loading dose: 4-5g IV over 15-20 minutes
  • Maintenance: 1-2g/hour continuous infusion for at least 24-48 hours 1, 3
  • Alternative regimen: 4-5g IV loading dose followed by 4-5g IM into alternate buttocks every four hours 3

• Monitor for magnesium toxicity:

  • Loss of deep tendon reflexes occurs at plasma levels approaching 10 mEq/L
  • Respiratory paralysis may occur at this level
  • Serum magnesium levels >12 mEq/L may be fatal 3

Maternal Monitoring

• BP monitoring
• Repeated proteinuria assessment if not already present
• Clinical assessment including clonus
• Blood tests at least twice weekly: hemoglobin, platelet count, liver enzymes, creatinine, and uric acid
• More frequent testing with changes in clinical status 2, 1

Fetal Monitoring

• Initial ultrasound assessment of fetal biometry, amniotic fluid, and umbilical artery Doppler
• Repeat ultrasound every 2 weeks if initial assessment normal
• More frequent amniotic fluid and Doppler assessment if fetal growth restriction present 2

Delivery Timing

Immediate delivery indicated for:

• Preeclampsia at ≥37 weeks' gestation
• Repeated episodes of severe hypertension despite treatment with 3 classes of antihypertensives
• Progressive thrombocytopenia
• Progressively abnormal renal or liver enzyme tests
• Pulmonary edema
• Abnormal neurological features (severe headache, visual scotomata, convulsions)
• Non-reassuring fetal status 2, 1

Expectant management considerations:

• Women with preeclampsia between 34-37 weeks: conservative approach recommended
• Women with preeclampsia at <34 weeks: conservative approach at a center with Maternal-Fetal Medicine expertise 2
• Expectant management in severe preeclampsia before 32 weeks can prolong pregnancy by 7-10 days, improving neonatal outcomes 4

Postpartum Care

• Continue BP monitoring every 4-6 hours for at least 3 days
• Taper antihypertensive medications slowly after days 3-6
• Follow-up within 1 week if still on antihypertensives at discharge 1
• Review at 3 months postpartum
• Annual medical review recommended lifelong for patients with history of hypertension in pregnancy 1

Prevention in Future Pregnancies

• Low-dose aspirin (81 mg/day) between 12-16 weeks gestation until delivery for high-risk women
• Calcium supplementation (1.0-1.5g elemental calcium daily) for women with low calcium intake 1

Key Caveats and Pitfalls

• Do not attempt to diagnose mild versus severe preeclampsia clinically as all cases may become emergencies rapidly 2
• Neither serum uric acid nor level of proteinuria should be used as an indication for delivery 2
• Plasma volume expansion is not recommended routinely in women with preeclampsia 2
• Continuous maternal administration of magnesium sulfate beyond 5-7 days can cause fetal abnormalities 3
• Preeclampsia rarely remits spontaneously and in most cases worsens with time, requiring close monitoring 1