What is the recommended management of a pregnant woman with pre‑eclampsia, including seizure prophylaxis, blood pressure control, and timing of delivery?

Treatment for Preeclampsia

All women with severe preeclampsia should be delivered promptly after maternal stabilization, regardless of gestational age, with immediate administration of magnesium sulfate for seizure prophylaxis and aggressive blood pressure control targeting systolic 110-140 mmHg and diastolic 85 mmHg. 1

Immediate Stabilization for Severe Hypertension (≥160/110 mmHg)

Urgent antihypertensive therapy must be initiated within 15-30 minutes when blood pressure reaches or exceeds 160/110 mmHg to prevent maternal cerebral hemorrhage. 1, 2

First-Line Antihypertensive Options:

• IV labetalol: 20 mg IV bolus, then 40 mg after 10 minutes, then 80 mg every 10 minutes (maximum cumulative dose 220 mg) 1, 3
• Oral nifedipine (immediate-release): 10-20 mg orally, repeat in 30 minutes if needed 1, 3
• IV hydralazine: 5-10 mg IV every 20 minutes as needed 1, 3
• IV nicardipine infusion: Start at 5 mg/h, increase by 2.5 mg/h every 5-15 minutes to maximum 15 mg/h 1

Target blood pressure: systolic 110-140 mmHg and diastolic 85 mmHg (absolute minimum <160/105 mmHg). 1, 4, 3

Critical Medication Warnings:

• Avoid short-acting sublingual nifedipine, especially when combined with magnesium sulfate—risk of uncontrolled hypotension and fetal distress 1, 3
• Sodium nitroprusside only as last resort due to fetal cyanide toxicity if used >4 hours 1
• ACE inhibitors, ARBs, and direct renin inhibitors are absolutely contraindicated due to severe fetotoxicity 3

Seizure Prophylaxis with Magnesium Sulfate

Magnesium sulfate must be administered immediately to all patients with severe preeclampsia, those with proteinuria plus severe hypertension, or any patient with neurological symptoms (headache, visual changes). 1, 2, 4, 3

Dosing Protocol:

• Loading dose: 4-5 g IV over 5 minutes (diluted in 250 mL of 5% dextrose or 0.9% normal saline) 1, 2, 4
• Maintenance: 1-2 g/hour continuous IV infusion 1, 2, 4
• Continue for 24 hours postpartum, as eclampsia can occur in the postpartum period 2

Monitoring for Magnesium Toxicity:

• Assess deep tendon reflexes before each dose 3
• Monitor respiratory rate continuously—magnesium toxicity causes respiratory depression 3
• Hourly urine output via Foley catheter with target ≥100 mL/4 hours (or >35 mL/hour) 3
• Have calcium gluconate 1 g IV available as antidote for magnesium toxicity 2

Comprehensive Laboratory and Fetal Assessment

Initial Laboratory Workup (Repeat at Least Twice Weekly):

• Complete blood count with focus on hemoglobin and platelet count (<100,000/μL indicates severe disease) 1, 2, 4
• Comprehensive metabolic panel: liver transaminases (AST/ALT), creatinine, uric acid 1, 2, 4
• Spot urine protein/creatinine ratio (≥30 mg/mmol confirms significant proteinuria) 1, 4
• Peripheral blood smear if HELLP syndrome suspected 3

Fetal Surveillance:

• Ultrasound at diagnosis: fetal biometry, amniotic fluid volume, umbilical artery Doppler 1, 4, 3
• Repeat ultrasound every 2 weeks if initial assessment normal; more frequently if fetal growth restriction present 1, 4, 3
• Continuous or intermittent electronic fetal heart rate monitoring 2

Delivery Timing: Gestational Age-Based Algorithm

≥37 Weeks' Gestation:

Deliver immediately after maternal stabilization, regardless of severity or laboratory values. 1, 4, 3

34-37 Weeks' Gestation:

• Without severe features: Expectant management with close monitoring is appropriate 1, 4
• With severe features: Deliver after maternal stabilization 1, 4, 3

<34 Weeks' Gestation:

• Conservative expectant management at a center with Maternal-Fetal Medicine expertise and NICU capabilities 1, 4, 3
• Administer corticosteroids for fetal lung maturity (betamethasone 12 mg IM every 24 hours for 2 doses) 1

<24 Weeks' Gestation:

Expectant management is associated with high maternal morbidity with limited perinatal benefit—counsel regarding pregnancy termination. 3

Absolute Indications for Immediate Delivery (Any Gestational Age)

Deliver immediately regardless of gestational age if any of the following develop: 1, 2, 4, 3

• Repeated episodes of severe hypertension despite treatment with ≥3 classes of antihypertensives in appropriate doses 1, 4, 3
• Progressive thrombocytopenia (declining platelet counts on serial measurements) 1, 4, 3
• Progressively abnormal liver or renal function tests (worsening trends, not static elevations) 1, 4
• Pulmonary edema or maternal oxygen saturation <90% 1, 2, 4, 3
• Severe intractable headache, repeated visual scotomata, or eclamptic seizures 1, 2, 4, 3
• Non-reassuring fetal status on continuous monitoring 1, 2, 4, 3
• Placental abruption 2, 3

Chronic Antihypertensive Management (Non-Severe Hypertension)

For blood pressures consistently ≥140/90 mmHg but <160/110 mmHg, initiate oral antihypertensives targeting diastolic BP of 85 mmHg to reduce the likelihood of developing severe hypertension. 1, 4

Acceptable Oral Agents:

• Methyldopa (first-line in many guidelines, but use with caution in women at risk of depression) 1, 4
• Labetalol 1, 4
• Nifedipine (long-acting) 1, 4
• Second or third-line agents: hydralazine, prazosin 1, 4

Reduce or cease antihypertensives if diastolic BP falls <80 mmHg. 1

HELLP Syndrome Recognition and Management

HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets) carries 3.4% maternal mortality and should be managed as severe preeclampsia with all features sought and addressed. 2, 4

Hallmark Clinical Features:

• Epigastric or right upper quadrant pain (hepatic capsule distension) 2, 4, 3
• Hemolysis on peripheral blood smear 2, 4
• AST/ALT ≥2x upper limit of normal 4
• Platelets <100,000/μL 2, 4

Special Considerations:

• Monitor glucose intraoperatively—severe hypoglycemia can occur in HELLP syndrome 2, 3
• Delivery is indicated regardless of gestational age 2, 4

Management of Pulmonary Edema

IV nitroglycerin (glycerol trinitrate) is the drug of choice, starting at 5 mcg/min and gradually increased every 3-5 minutes to maximum 100 mcg/min. 4, 3

Plasma volume expansion is NOT recommended routinely—it does not improve maternal outcomes and may exacerbate complications. 1, 2, 4

Fluid balance should be limited to 60-80 mL/hour to avoid pulmonary edema. 2

Mode of Delivery

Vaginal delivery should be considered for women with any hypertensive disorders in pregnancy unless cesarean delivery is required for obstetric indications. 1

Induction of labor is associated with improved maternal outcome compared to expectant management at term. 3

Antihypertensive treatment should be continued during labor and delivery to keep systolic BP <160 mmHg and diastolic BP <110 mmHg. 1

Postpartum Management

Blood Pressure Monitoring:

Monitor BP at least every 4-6 hours while awake for at least 3 days postpartum, as hypertension can worsen between days 3-6 after delivery. 2, 4, 3

Continue antihypertensives administered antenatally, but replace methyldopa with an alternative agent if it was used during pregnancy. 1, 3

Medication Considerations:

Avoid NSAIDs for postpartum analgesia unless other analgesics are not working, especially in the setting of renal dysfunction or placental abruption—NSAIDs can worsen hypertension and renal function. 2, 4

Select antihypertensive medication with respect to breastfeeding; methyldopa is often considered the drug of choice but should be used with caution in women at risk of developing depression. 1

Follow-Up:

All women with hypertension in pregnancy should have BP and urine checked at 6 weeks postpartum, with persistent hypertension confirmed by 24-hour ambulatory monitoring. 1

Review all women at 3 months postpartum to ensure BP, urinalysis, and laboratory abnormalities have normalized. 4

Women with persisting hypertension or proteinuria 6 weeks after delivery should be referred to a specialist. 1

Women under age 40 with persisting hypertension should be assessed for a secondary cause of hypertension. 1

Prevention of Preeclampsia in Future Pregnancies

Women at high or moderate risk of preeclampsia should take low-dose aspirin (100-150 mg) daily from week 12 to weeks 36-37. 1

High-dose calcium supplementation (≥1 g/day) may reduce the risk of preeclampsia and preterm birth, particularly for women with low calcium diet. 1

Critical Pitfalls to Avoid

• Do not underestimate disease severity based on "mild" classification—all preeclampsia can rapidly progress to life-threatening complications 2, 4, 3
• Do not rely on blood pressure alone to determine severity—serious organ dysfunction develops at relatively mild BP elevations 2, 4
• Do not use serum uric acid or level of proteinuria as indication for delivery 1, 4, 3
• Do not delay delivery at ≥37 weeks based on non-reactive NST—delivery is indicated regardless of fetal testing results 4
• Do not use diuretics routinely—they further reduce plasma volume which is already contracted in preeclampsia 3
• Do not attempt to diagnose "mild versus severe" preeclampsia clinically—all cases may become emergencies rapidly 3

Long-Term Cardiovascular Risk

Women with preeclampsia have significant long-term cardiovascular risks requiring annual medical review life-long. 4