What is the appropriate evaluation and management for a pregnant woman >20 weeks gestation presenting with new‑onset hypertension (≥140/90 mm Hg) and proteinuria (≥300 mg/24 h) or severe features of pre‑eclampsia?

Pre-eclampsia: Evaluation and Management

Immediate Diagnostic Confirmation

A pregnant woman >20 weeks with new-onset hypertension (≥140/90 mmHg) and proteinuria (≥300 mg/24h) or severe features requires immediate magnesium sulfate for seizure prophylaxis, urgent blood pressure control if ≥160/110 mmHg, and expedited delivery planning after maternal stabilization. 1

Diagnostic Criteria

• Hypertension: BP ≥140/90 mmHg confirmed on two separate occasions at least 15 minutes apart (or immediately if ≥160/110 mmHg) 2
• Proteinuria: ≥300 mg/24h or albumin-to-creatinine ratio ≥30 mg/mmol in spot urine 2
• Pre-eclampsia without proteinuria: Hypertension plus new-onset organ dysfunction (thrombocytopenia, elevated liver enzymes, renal insufficiency, pulmonary edema, or neurological symptoms) 2, 3

Severe Features Assessment

Immediately evaluate for severe features that mandate urgent intervention 2:

• Severe hypertension: BP ≥160/110 mmHg sustained for ≥15 minutes 1, 4
• Neurological: Severe headache, visual disturbances (scotomata, cortical blindness), altered mental status, hyperreflexia with clonus 2
• Right upper quadrant/epigastric pain: Suggests hepatic capsule distension or HELLP syndrome 2, 1
• Pulmonary edema 1, 4
• Thrombocytopenia: Platelets <100,000/μL 5
• Elevated liver transaminases: >2× upper limit of normal 5
• Renal dysfunction: Creatinine >1.1 mg/dL or doubling of baseline, oliguria <100 mL/4h 1, 3

Immediate Management Protocol

Magnesium Sulfate for Seizure Prophylaxis

Administer immediately to all patients with severe pre-eclampsia or any neurological symptoms 1, 4:

• Loading dose: 4-5g IV over 5 minutes 1
• Maintenance: 1-2g/hour continuous IV infusion 1
• Duration: Continue for 24 hours postpartum 1
• Monitoring for toxicity: Check deep tendon reflexes before each dose, respiratory rate (watch for depression), urine output ≥100 mL/4h or >35 mL/hour 1

Acute Blood Pressure Management

For BP ≥160/110 mmHg, initiate IV antihypertensive therapy within 30-60 minutes 1, 4:

First-Line IV Agents

• Labetalol (preferred): 20mg IV bolus, then 40mg after 10 minutes, followed by 80mg every 10 minutes to maximum cumulative dose of 220mg 1, 6
• Hydralazine (alternative): If labetalol contraindicated or unavailable 1, 7
• Nicardipine (alternative): If other agents unavailable 1

Blood Pressure Targets

• Primary target: Systolic 110-140 mmHg and diastolic ≈85 mmHg 2, 1, 4
• Minimum acceptable: <160/105 mmHg 1, 4
• Critical caveat: Do NOT reduce antihypertensives if diastolic falls <80 mmHg, as this preserves uteroplacental perfusion 1, 4

Medications to Avoid

• Short-acting oral nifedipine: Especially with concurrent magnesium sulfate—risk of uncontrolled hypotension and fetal compromise 1
• Sodium nitroprusside: Only for extreme emergencies; risk of fetal cyanide toxicity if used >4 hours 1
• ACE inhibitors, ARBs, direct renin inhibitors: Absolutely contraindicated due to severe fetotoxicity 2, 4
• Diuretics: Contraindicated as they further reduce plasma volume 4

Comprehensive Laboratory Evaluation

Obtain immediately and repeat at least twice weekly (more frequently with clinical deterioration) 1, 4:

• Complete blood count: Hemoglobin, platelet count (watch for HELLP syndrome) 1
• Liver function: Transaminases (AST, ALT) 1
• Renal function: Serum creatinine, uric acid 1
• Peripheral blood smear: If HELLP syndrome suspected (hemolysis) 1

Maternal Monitoring Requirements

Continuous monitoring until hemodynamically stable 1, 4:

• Blood pressure: Continuous monitoring 1
• Urine output: Hourly via Foley catheter, target ≥100 mL/4h 1
• Fluid restriction: 60-80 mL/hour to reduce pulmonary edema risk 1
• Oxygen saturation: Maintain >95% on room air 1
• Neurological assessment: Monitor for severe headache, visual changes, confusion, agitation 1
• Deep tendon reflexes: Assess for hyperreflexia and clonus 1, 4

Fetal Surveillance

• Initial ultrasound at diagnosis: Fetal biometry, amniotic fluid volume, umbilical artery Doppler 1, 4
• Repeat ultrasound: Every 2 weeks if normal; more frequently if fetal growth restriction present 1, 4
• Continuous fetal heart rate monitoring throughout labor and delivery 6

Delivery Decision Algorithm

Absolute Indications for Immediate Delivery (Any Gestational Age)

Deliver after maternal stabilization with magnesium sulfate and blood pressure control 1, 4:

• Gestational age ≥37 weeks 1, 4
• Inability to control BP despite ≥3 antihypertensive classes at appropriate doses 1, 4
• Progressive thrombocytopenia 1, 4
• Progressively abnormal liver or renal function tests 1, 4
• Pulmonary edema (treat with IV nitroglycerin 5-100 mcg/min; avoid plasma expansion) 1
• Severe intractable headache, repeated visual scotomata, or eclamptic seizures 1, 4
• Non-reassuring fetal status 1, 4
• Placental abruption 1
• Maternal pulse oximetry deterioration 1

Gestational Age-Specific Management

≥37 Weeks

• Deliver after maternal stabilization 1, 4
• Vaginal delivery preferred unless obstetric indications mandate cesarean 1
• Induction of labor associated with improved maternal outcomes 1

34-37 Weeks

• Expectant conservative management if maternal and fetal status stable 1, 4
• Deliver if any maternal or fetal deterioration 1, 4

<34 Weeks

• Conservative expectant management at tertiary center with Maternal-Fetal Medicine expertise 1, 4
• Administer antenatal corticosteroids for fetal lung maturity 5
• Deliver immediately if any absolute indication present 1

<24 Weeks

• Expectant management carries high maternal morbidity with limited perinatal benefit 1
• Counsel regarding pregnancy termination 1, 5

Critical Pitfalls to Avoid

• Do NOT classify as "mild" versus "severe" pre-eclampsia clinically—all cases can rapidly become emergencies 1, 6, 4
• Do NOT use serum uric acid level or degree of proteinuria as criteria for delivery timing—these do not correlate with outcomes 1, 4
• Do NOT delay delivery at ≥37 weeks based on absence of symptoms—serious complications can develop at relatively mild hypertension levels 6
• Do NOT employ routine plasma volume expansion—increases pulmonary edema risk 1, 4
• Do NOT assume stability based on current normal condition—pre-eclampsia can progress rapidly and unpredictably during labor 6

Postpartum Management

• Replace methyldopa with alternative antihypertensive after delivery 1, 4
• Monitor BP at least every 4 hours while awake for minimum 3 days postpartum—hypertension often worsens between days 3-6 after delivery 1, 4
• Continue magnesium sulfate for 24 hours postpartum 1
• 10% of maternal deaths from hypertensive disorders occur postpartum—maintain vigilance 2

Long-Term Implications

• Pre-eclampsia is a risk factor for future cardiovascular disease—mandates long-term follow-up and cardiovascular risk modification 5
• Increased risk of chronic hypertension, stroke, and renal disease in later life 5