What is the treatment for preeclampsia?

Treatment of Preeclampsia

The definitive treatment for preeclampsia is delivery of the baby and placenta, with timing determined by gestational age and disease severity; prior to delivery, management focuses on blood pressure control with antihypertensives, seizure prophylaxis with magnesium sulfate, and close maternal-fetal monitoring. 1, 2

Immediate Assessment and Hospitalization

• All women with newly diagnosed preeclampsia require initial hospitalization to confirm diagnosis, assess severity, and establish monitoring protocols 1
• Maternal monitoring includes blood pressure measurements every 4 hours (more frequently if severe hypertension present), clinical assessment for clonus and neurological symptoms, and evaluation for signs of disease progression 1
• Laboratory monitoring should include hemoglobin, platelet count, liver enzymes, and renal function (including uric acid) at least twice weekly 1
• Initial fetal assessment must confirm well-being, followed by serial ultrasound surveillance including fetal biometry, amniotic fluid assessment, and umbilical artery Doppler 1

Blood Pressure Management

Severe Hypertension (≥160/110 mmHg)

Severe hypertension requires urgent treatment in a monitored setting to prevent maternal stroke and other end-organ damage. 1

• First-line treatment: Oral nifedipine 10 mg, repeat every 20 minutes to maximum 30 mg 1
• Alternative: IV labetalol 20 mg bolus, then 40 mg after 10 minutes if needed, followed by 80 mg every 10 minutes to maximum 220 mg 1, 3
• IV hydralazine (5 mg bolus, then 10 mg every 20-30 minutes to maximum 25 mg) can be used as second-line therapy 3
• Sodium nitroprusside (0.25 μg/kg/min to maximum 5 μg/kg/min) is reserved only when other agents fail, and should not be used for more than 4 hours due to risk of fetal cyanide poisoning 3

Critical caveat: Avoid sublingual or rapid IV calcium channel blockers as they can cause precipitous blood pressure drops leading to myocardial infarction or fetal distress 1

Non-Severe Hypertension (140-159/90-109 mmHg)

• Treat with oral antihypertensives targeting diastolic BP of 85 mmHg and systolic BP between 110-140 mmHg 1
• The goal is controlled reduction rather than normalization, as even modest elevations (150/100 mmHg) can cause significant symptoms in previously normotensive women 3

Seizure Prophylaxis with Magnesium Sulfate

Magnesium sulfate is the standard of care for seizure prevention in women with preeclampsia and severe features. 1, 4

• Magnesium sulfate prevents convulsions by blocking neuromuscular transmission and decreasing acetylcholine release at the motor end-plate 4
• Effective anticonvulsant serum levels range from 2.5 to 7.5 mEq/L 4
• Continue magnesium sulfate for 24 hours postpartum 1
• Monitor for magnesium toxicity: deep tendon reflexes disappear at plasma levels approaching 10 mEq/L, respiratory paralysis may occur at this level, and levels exceeding 12 mEq/L may be fatal 4
• Do not combine IV magnesium with calcium channel blockers due to risk of myocardial depression 1

Fluid Management

Strict fluid restriction is essential to prevent pulmonary edema, a common and potentially fatal complication. 1

• Limit total fluid intake to 60-80 mL/hour 1
• Aim for euvolemia; avoid "running dry" as this increases risk of acute kidney injury 1
• Diuretics are contraindicated in preeclampsia as they further reduce plasma volume 1

Timing of Delivery: The Definitive Treatment

Delivery is always appropriate for the mother but may not be optimal for an extremely premature fetus; the decision requires balancing maternal safety against neonatal outcomes. 5, 3

Delivery at ≥37 Weeks

• Women with mild preeclampsia at 37 weeks or beyond should undergo induction of labor, as pregnancy outcomes are similar to normotensive pregnancies at this gestational age 5

Delivery at 34-37 Weeks

• Deliver at 37 weeks or earlier if severe features develop 1
• Induction is recommended at or beyond 34 weeks in the presence of severe preeclampsia, labor, rupture of membranes, or non-reassuring fetal testing 5

Before 34 Weeks: Expectant Management vs. Delivery

• Immediate delivery is mandatory for: repeated episodes of severe hypertension despite treatment with 3 classes of antihypertensives, placental abruption, non-reassuring fetal status, imminent eclampsia (persistent severe symptoms), or multiorgan dysfunction 1, 5
• Expectant management may be considered in select women between 24-32 weeks with stable maternal condition and reassuring fetal status, in a tertiary care facility with appropriate neonatal services 5
• Administer corticosteroids for 48 hours to accelerate fetal lung maturation if gestational age <34 weeks 1
• Expectant management typically prolongs pregnancy by 7-10 days and improves neonatal outcomes, but requires intensive maternal-fetal monitoring 5
• At 24 weeks gestation, expectant treatment is associated with high maternal morbidity with limited perinatal benefit 5

Postpartum Management

Close monitoring must continue postpartum as eclampsia can develop or persist after delivery. 1

• Continue close monitoring for at least 3 days postpartum 1
• Monitor blood pressure at least every 4 hours while awake 1
• Continue antihypertensives and taper slowly after days 3-6 postpartum 1
• Preeclampsia rarely remits spontaneously and in most cases worsens with time; treatment does not alter underlying pathophysiology but may slow progression 3

Prevention Strategies for Future Pregnancies

Low-dose aspirin is the best-studied and most effective preventive strategy for women at high risk of preeclampsia. 3, 1

• Low-dose aspirin (75-162 mg/day) should be initiated before 16 weeks' gestation (definitely before 20 weeks) for women with strong clinical risk factors 1, 6
• Aspirin is particularly effective in reducing early-onset preeclampsia when started early in pregnancy 6
• Supplemental calcium (1.2-2.5 g/day) should be considered if dietary intake is likely low (<600 mg/day) 1, 6

Investigational Therapies

Several promising therapies are under investigation but lack sufficient evidence for routine clinical use. 3

• Pravastatin did not demonstrate benefit in pregnancy prolongation or clinical outcomes in recent trials 3
• Metformin may extend gestation by 1 week and shows promise in morbidly obese women, but requires larger randomized controlled trials 3, 6
• Dextran sulfate apheresis and other novel interventions remain experimental and should not be used outside research protocols 3

Long-Term Counseling

• Women with preeclampsia should be counseled about increased lifetime cardiovascular risk and the importance of cardiovascular risk factor modification 1
• Regular exercise during pregnancy may help reduce the likelihood of hypertension 1

Critical Contraindications

• ACE inhibitors are absolutely contraindicated during second and third trimesters due to fetal renal dysgenesis 1
• Avoid combining calcium channel blockers with IV magnesium sulfate 1
• Diuretics are contraindicated as they worsen plasma volume depletion 1