What is the latest recommended treatment for pre‑eclampsia, including seizure prophylaxis, blood pressure control, corticosteroids, and gestational‑age‑based management?

Latest Treatment for Preeclampsia

Delivery is the definitive treatment for preeclampsia, with timing based on gestational age and severity; severe preeclampsia with features requires immediate delivery at ≥34 weeks, while expectant management with close monitoring is reasonable for cases without severe features before 37 weeks. 1

Blood Pressure Management

Treatment Thresholds and Targets

• Acute severe hypertension (≥160/110 mmHg) requires urgent treatment within 15 minutes to prevent maternal stroke and other end-organ damage. 1, 2
• The target blood pressure after acute control is 110-140 mmHg systolic and 85-100 mmHg diastolic. 2, 3
• For non-severe hypertension (140-159/90-109 mmHg), treatment thresholds vary by guideline: ACOG recommends treatment at ≥160/110 mmHg for gestational hypertension/preeclampsia, while International Society for the Study of Hypertension in Pregnancy recommends ≥140/90 mmHg. 1

First-Line Antihypertensive Agents

Intravenous labetalol is the preferred first-line agent for acute severe hypertension, with the following protocol: 2, 3, 4

• Initial bolus: 20 mg IV
• Second dose: 40 mg IV after 10 minutes if needed
• Subsequent doses: 80 mg IV every 10 minutes
• Maximum total dose: 220 mg

Oral nifedipine (immediate-release) is an effective alternative, dosed at 10 mg orally, repeated every 20 minutes to a maximum of 30 mg. 3, 4

Intravenous nicardipine can be used as an alternative, starting at 5 mg/hour and titrating by 2.5 mg/hour every 5-15 minutes to a maximum of 15 mg/hour. 2

Critical Drug Interactions and Contraindications

• Never combine magnesium sulfate with calcium channel blockers (especially IV or sublingual nifedipine), as this causes severe myocardial depression and precipitous hypotension. 5, 2, 3
• ACE inhibitors and ARBs are absolutely contraindicated during second and third trimesters due to fetal renal dysgenesis. 2, 3
• Avoid sublingual nifedipine due to risk of uncontrolled blood pressure drops. 3
• Sodium nitroprusside should only be used as an absolute last resort due to fetal cyanide toxicity. 2

Seizure Prophylaxis with Magnesium Sulfate

Indications

Magnesium sulfate is the gold-standard anticonvulsant for eclampsia prevention and treatment, superior to all other agents including phenytoin and diazepam. 5, 2, 6

Administer magnesium sulfate for: 5, 3

• All women with severe preeclampsia (blood pressure ≥160/110 mmHg with proteinuria)
• Women with moderate hypertension (≥150/100 mmHg) who have proteinuria plus signs of imminent eclampsia (severe headache, visual scotomata, clonus, or epigastric pain)
• All cases of eclampsia (active seizures)

Dosing Protocol

Loading dose: 4-6 grams IV over 20-30 minutes 5, 3, 7

Maintenance infusion: 1-2 grams per hour by continuous IV infusion 5, 3

Duration: Continue for 24 hours postpartum or 24 hours after the last seizure, whichever is later, as 25-30% of eclamptic seizures occur postpartum. 5, 2, 3

Clinical Monitoring (Not Laboratory)

Magnesium levels should NOT be routinely drawn; instead, use clinical monitoring to guide therapy: 5, 3

• Deep tendon reflexes (loss indicates toxicity)
• Respiratory rate (maintain >12 breaths/minute; respiratory paralysis occurs at 5-6.5 mmol/L)
• Urine output (maintain ≥30 mL/hour; oliguria increases toxicity risk as magnesium is renally excreted)
• Oxygen saturation (maintain >90%)

Check serum magnesium levels only in specific high-risk situations: 5

• Renal impairment (elevated creatinine)
• Urine output <30 mL/hour
• Loss of patellar reflexes
• Respiratory rate <12 breaths/minute

Fluid Management

Strictly limit total intravenous fluid intake to 60-80 mL per hour to prevent iatrogenic pulmonary edema, as preeclamptic women have increased capillary leak and reduced plasma volume. 1, 5, 2, 3

Aim for euvolemia; avoid "running dry" as this increases the risk of acute kidney injury. 3

Diuretics are absolutely contraindicated because plasma volume is already reduced in preeclampsia. 2, 3

Corticosteroids for Fetal Lung Maturation

Administer antenatal corticosteroids when gestational age is <34 weeks to accelerate fetal lung maturation, provided delivery can be safely delayed for at least 48 hours. 3, 7

Gestational Age-Based Delivery Timing

Preeclampsia Without Severe Features

• Before 37 weeks: Close, continued observation with expectant management is reasonable, with frequent maternal and fetal monitoring. 1
• At or after 37 weeks: Delivery is recommended. 1

Preeclampsia With Severe Features

• At or beyond 34 weeks: Delivery is recommended given the high risk for rapid maternal clinical deterioration. 1
• Before 34 weeks: Consider expectant management in highly selected cases with intensive monitoring, but only in tertiary centers with appropriate resources. 7

Mandatory Immediate Delivery Indications (Regardless of Gestational Age)

Deliver immediately if any of the following develop: 3

• Eclampsia (seizures)
• Repeated episodes of severe hypertension despite treatment with 3 classes of antihypertensives
• Pulmonary edema
• Placental abruption
• Non-reassuring fetal status
• HELLP syndrome with deteriorating maternal condition

Special Management of Pulmonary Edema

If pulmonary edema develops: 3

• Provide supplemental oxygen to maintain saturation >95%
• Start IV nitroglycerin infusion at 5 µg/min, increasing by 5 µg/min every 5 minutes as needed (maximum 100 µg/min)
• Avoid calcium channel blockers in this setting
• Proceed with delivery after maternal stabilization

Postpartum Management

Continue magnesium sulfate for a minimum of 24 hours postpartum, as eclamptic seizures may develop for the first time in the early postpartum period. 5, 2, 3

Monitor blood pressure at least every 4-6 hours while awake for at least 3 days postpartum. 1, 2, 3

Continue or restart antihypertensive therapy after delivery and taper slowly only after days 3-6 postpartum, unless blood pressure falls below 110/70 mmHg. 3

Treatment threshold postpartum: Most obstetricians treat severe-range hypertension (≥150/100 mmHg) as a medical emergency up to 6 weeks postpartum due to risk of postpartum preeclampsia. 1

Avoid NSAIDs in women with preeclampsia, especially if acute kidney injury is present; use alternative analgesics. 3

Prevention Strategies for High-Risk Women

Low-dose aspirin (75-162 mg daily) should be started before 16 weeks' gestation (ideally by 12 weeks, definitely before 20 weeks) in women with strong clinical risk factors for preeclampsia. 3, 8

Calcium supplementation (1.2-2.5 g elemental calcium per day) is recommended when dietary calcium intake is likely <600-800 mg/day. 5, 3

Long-Term Cardiovascular Risk Counseling

Women with preeclampsia should be counseled about increased lifetime cardiovascular risk, including higher incidence of stroke, cardiovascular disease, type 2 diabetes, venous thromboembolism, and chronic kidney disease. 3, 8

Re-evaluate at 3 months postpartum to confirm normalization of blood pressure, urinalysis, and laboratory studies; persistent abnormalities warrant further investigation. 3

Lifelong cardiovascular risk monitoring is recommended, including periodic blood pressure checks, fasting lipid panels, and blood glucose screening, together with lifestyle counseling on weight management and regular aerobic exercise. 3