Pre-eclampsia

Pre-eclampsia is a hypertensive disorder of pregnancy characterized by new-onset hypertension (≥140/90 mmHg) after 20 weeks of gestation, accompanied by proteinuria (≥300 mg in a 24-hour urine collection or a urine protein/creatinine ratio ≥0.3).

In the absence of proteinuria, pre-eclampsia can still be diagnosed if other signs of significant end-organ dysfunction are present (e.g., thrombocytopenia, impaired liver function, renal insufficiency, pulmonary edema, or cerebral/visual disturbances).

Pathophysiology:

• Pre-eclampsia is thought to result from abnormal placentation and defective trophoblastic invasion leading to placental hypoxia. This in turn triggers systemic endothelial dysfunction, resulting in widespread vasospasm and multiorgan effects.

Risk Factors:

• Maternal Factors: Nulliparity, advanced maternal age (>35 years), obesity, history of pre-eclampsia, chronic hypertension, renal disease, diabetes mellitus, antiphospholipid syndrome.
• Pregnancy Factors: Multiple gestation, hydatidiform mole, donor egg pregnancy.

Clinical Presentation:

• Mild Pre-eclampsia: BP ≥140/90 mmHg but <160/110 mmHg, proteinuria without symptoms.
• Severe Pre-eclampsia: BP ≥160/110 mmHg, significant proteinuria, and evidence of end-organ involvement (e.g., elevated liver enzymes, severe headache, visual disturbances, oliguria, or thrombocytopenia).

Investigations:

Blood Pressure Monitoring: Regular BP assessments are crucial to monitor trends.

Urine Tests:

• Urinalysis: Presence of protein.
• 24-Hour Urine Collection: Quantification of proteinuria (>300 mg/24 hours confirms diagnosis).

Blood Tests:

• Complete Blood Count (CBC): Thrombocytopenia (<100,000/mm³) can indicate severe disease.
• Liver Function Tests: Elevated transaminases (AST, ALT) >2 times the upper limit of normal.
• Renal Function Tests: Elevated serum creatinine (>1.1 mg/dL) or doubling of baseline levels.
• Uric Acid Levels: Often elevated in pre-eclampsia.

Coagulation Profile: If HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelet count) is suspected.

Fetal Assessment:

• Ultrasound: To assess fetal growth and amniotic fluid volume.
• Doppler Ultrasound: To evaluate umbilical artery flow.
• Non-Stress Test (NST) or Biophysical Profile (BPP): To monitor fetal well-being.

Management:

1. Expectant Management (for Mild Pre-eclampsia):

• Indications: <37 weeks gestation, stable maternal and fetal condition.
• Monitoring:
  • BP measurement: Every 1-2 days.
  • Urine Protein and Blood Tests: Weekly.
  • Fetal Surveillance: Regular NST or BPP.
• Lifestyle: Bed rest and reduced physical activity.

2. Severe Pre-eclampsia Management:

• Indications: ≥160/110 mmHg, severe proteinuria, or evidence of end-organ damage.
• Hospitalization: Required for close monitoring and management.
• Antihypertensive Therapy:
  • First-line agents:
  • Labetalol: IV bolus 20 mg, followed by increments of 20–80 mg every 20–30 minutes until the target BP is achieved (max 300 mg/day). Oral labetalol (200-400 mg bid) can be used if stable.
  • Nifedipine: Immediate-release 10 mg orally, repeat every 30 minutes as needed. Maintenance dose: 30-60 mg once daily.
  • Hydralazine: IV bolus 5-10 mg, repeated every 20-30 minutes until desired effect.
• Magnesium Sulfate: For seizure prophylaxis in severe pre-eclampsia/eclampsia.
  • Loading dose: 4-6 g IV over 15-20 minutes.
  • Maintenance dose: 2-3 g/hour IV for 24 hours after last seizure or delivery.
• Delivery Timing:
  • <34 weeks: Steroid administration for fetal lung maturity (betamethasone 12 mg IM, 2 doses 24 hours apart). Continue expectant management unless maternal/fetal conditions worsen.
  • ≥34 weeks: Delivery is generally recommended.
  • Immediate Delivery Indications: Uncontrollable BP, worsening renal/liver function, HELLP syndrome, placental abruption, or non-reassuring fetal status.

3. Postpartum Management:

• BP Monitoring: Continue monitoring for at least 72 hours postpartum, and periodically up to 6 weeks.
• Antihypertensives: Continue until BP normalizes.
• Magnesium Sulfate: Continue for 24 hours postpartum if severe pre-eclampsia/eclampsia.

Long-term Considerations:

• Women with a history of pre-eclampsia are at increased risk for future cardiovascular and kidney diseases. Regular health check-ups and lifestyle changes (diet, exercise) are recommended.

Complications:

• Maternal: Eclampsia, HELLP syndrome, cerebrovascular accidents, disseminated intravascular coagulation (DIC), liver rupture, acute kidney injury.
• Fetal: Intrauterine growth restriction (IUGR), preterm birth, placental abruption, fetal distress, stillbirth.

Prevention:

• Low-Dose Aspirin (75-150 mg daily): Starting from 12-16 weeks for high-risk women.
• Calcium Supplementation (1-2 g daily): Especially in women with low dietary calcium intake.

Summary

Pre-eclampsia management involves early detection, timely intervention, and balancing maternal-fetal risks. Expectant management may be pursued in stable, preterm cases, while severe disease often necessitates delivery. Individualized patient care is key to optimizing outcomes.