What is the management approach for a pregnant woman diagnosed with pre-eclampsia?

Management of Preeclampsia

All women diagnosed with preeclampsia at ≥37 weeks' gestation should undergo immediate delivery after maternal stabilization, while those with severe features require urgent blood pressure control with IV antihypertensives (target 110-140/85 mmHg) and magnesium sulfate for seizure prophylaxis regardless of gestational age. 1, 2, 3

Initial Assessment and Risk Stratification

Diagnostic Confirmation

• Preeclampsia is defined as new-onset hypertension (≥140/90 mmHg) after 20 weeks' gestation, and while proteinuria was historically required, it is no longer mandatory for diagnosis 4, 5
• Proteinuria is confirmed by ≥300 mg/24 hours, spot urine protein/creatinine ratio ≥30 mg/mmol (or 0.3 mg/mg), or ≥1+ on dipstick testing 4, 1
• All cases of preeclampsia should be treated as potentially severe, as rapid progression to life-threatening complications can occur even with initially mild presentations 1, 3

Severity Assessment

Severe features include any of the following 1, 3, 5:

• Severe hypertension: BP ≥160/110 mmHg on two occasions at least 15 minutes apart
• Thrombocytopenia: platelets <100,000/μL
• Elevated liver transaminases: >2 times upper limit of normal
• Renal dysfunction: creatinine >1.1 mg/dL or doubling of baseline
• Pulmonary edema
• New-onset persistent severe headache unresponsive to medication
• Visual disturbances (scotomata, cortical blindness)
• Epigastric or right upper quadrant pain (suggests hepatic capsule distension or HELLP syndrome) 3, 5

Immediate Stabilization for Severe Preeclampsia

Blood Pressure Management

Urgent antihypertensive therapy must be initiated immediately when BP ≥160/110 mmHg persists for >15 minutes to prevent maternal cerebral hemorrhage 1, 3

First-line IV antihypertensive options 1, 3:

• IV labetalol: 20 mg IV bolus, then 40 mg after 10 minutes, then 80 mg every 10 minutes (maximum cumulative dose 220 mg)
• IV hydralazine: 5-10 mg IV every 20 minutes as needed
• Oral nifedipine immediate-release: 10-20 mg orally, repeat in 20 minutes if needed (for non-severe hypertension or when IV access unavailable)

Target blood pressure: Systolic 110-140 mmHg and diastolic 85 mmHg (or at minimum <160/105 mmHg) 1, 3

Critical medication warnings 3:

• Short-acting oral nifedipine should be avoided when combined with magnesium sulfate due to risk of uncontrolled hypotension
• Sodium nitroprusside should only be used as last resort due to risk of fetal cyanide poisoning
• 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 or those with proteinuria plus severe hypertension or any neurological symptoms 1, 3, 6

Dosing regimen 6:

• Loading dose: 4-5 g IV over 5 minutes (diluted in 250 mL of 5% dextrose or 0.9% normal saline)
• Maintenance: 1-2 g/hour continuous IV infusion
• Alternative regimen: After 4 g IV loading dose, give 4-5 g IM (10 mL of 50% solution) into each buttock, then 4-5 g IM into alternate buttocks every 4 hours as needed

Therapeutic serum magnesium level: 4-7.5 mEq/L (6 mg/100 mL is optimal for seizure control) 6

Critical monitoring for magnesium toxicity 3, 6:

• Deep tendon reflexes before each dose (reflexes disappear at ~10 mEq/L)
• Respiratory rate (respiratory paralysis may occur at ~10 mEq/L)
• Urine output: maintain ≥100 mL/4 hours or >35 mL/hour via Foley catheter 3
• Have calcium gluconate 1 g (10 mL of 10% solution) at bedside as antidote for magnesium toxicity 6

Important limitation: Continuous maternal administration beyond 5-7 days can cause fetal abnormalities 6

Comprehensive Laboratory and Fetal Assessment

Initial Laboratory Workup

Obtain immediately at diagnosis 1, 3:

• Complete blood count with focus on hemoglobin and platelet count
• Comprehensive metabolic panel: liver transaminases (AST/ALT), creatinine, uric acid
• Peripheral blood smear if HELLP syndrome suspected (hemolysis, elevated liver enzymes, low platelets)
• Spot urine protein/creatinine ratio

Ongoing monitoring: Repeat labs at least twice weekly, or more frequently with clinical deterioration 3

Fetal Assessment

Initial ultrasound evaluation 1, 2:

• Fetal biometry to assess for growth restriction
• Amniotic fluid volume assessment
• Umbilical artery Doppler velocimetry

Ongoing fetal surveillance 1, 3:

• Continuous electronic fetal heart rate monitoring
• Repeat ultrasound every 2 weeks if initial assessment normal, more frequently if fetal growth restriction present
• Daily fetal movement counts

Maternal Monitoring Requirements

Continuous assessment includes 1, 3:

• Blood pressure monitoring (hourly in acute phase)
• Oxygen saturation on room air (maternal early warning if <95%)
• Hourly urine output via Foley catheter (target ≥100 mL/4 hours)
• Assessment for symptoms: severe headache, visual changes, epigastric pain, shortness of breath
• Clinical examination: deep tendon reflexes, clonus, mental status changes

Delivery Timing: Gestational Age-Based Algorithm

≥37 Weeks' Gestation

Immediate delivery is indicated after maternal stabilization 1, 2, 3

• Induction of labor is preferred and associated with improved maternal outcomes 3, 7
• Vaginal delivery is preferred unless cesarean indicated for standard obstetric reasons 2, 3

34-37 Weeks' Gestation

Without severe features: Expectant management with close monitoring is appropriate 1, 3

With severe features: Deliver after maternal stabilization 3, 5

• Administer antenatal corticosteroids for fetal lung maturity if not previously given 5

<34 Weeks' Gestation

Conservative expectant management at a center with Maternal-Fetal Medicine expertise 3, 7

• Administer antenatal corticosteroids for fetal lung maturity 5
• Average prolongation is 7-10 days in carefully selected patients 7
• This approach improves neonatal outcomes but requires intensive maternal and fetal monitoring 7

<24 Weeks' Gestation

Counsel regarding pregnancy termination 3

• Expectant management is associated with high maternal morbidity with limited perinatal benefit 3, 7

Absolute Indications for Immediate Delivery (Any Gestational Age)

Deliver immediately regardless of gestational age if any of the following occur 1, 3, 7:

• Inability to control BP despite ≥3 classes of antihypertensives in appropriate doses
• Progressive thrombocytopenia or progressively abnormal liver/renal function tests
• Pulmonary edema
• Severe intractable headache, repeated visual scotomata, or eclamptic seizures
• Placental abruption
• Non-reassuring fetal status on continuous monitoring
• Maternal oxygen saturation deterioration (<90%)
• HELLP syndrome with deteriorating maternal condition

Special Considerations and Critical Pitfalls

HELLP Syndrome Recognition

HELLP syndrome is defined by 3, 5:

• Hemolysis (peripheral blood smear, elevated LDH, decreased haptoglobin)
• Elevated Liver enzymes (AST/ALT >2 times upper limit)
• Low Platelets (<100,000/μL)

Maternal mortality rate is 3.4% 3

• Epigastric or right upper quadrant pain is a hallmark symptom 3
• Monitor glucose intraoperatively as severe hypoglycemia can occur 3

Management of Pulmonary Edema

Drug of choice: IV nitroglycerin (glycerol trinitrate) starting at 5 mcg/min, gradually increased every 3-5 minutes to maximum 100 mcg/min 3

• Plasma volume expansion is NOT recommended routinely 1, 3

Common Pitfalls to Avoid

• Do not underestimate disease severity based on "mild" classification—all preeclampsia can rapidly progress 1, 2, 3
• Blood pressure alone is not a reliable indicator of disease severity—serious organ dysfunction can develop at relatively mild levels of hypertension 1
• Do not use serum uric acid or level of proteinuria as indication for delivery 1, 3
• Do not delay delivery at ≥37 weeks based on non-reactive NST—delivery is indicated regardless of fetal testing results 2
• Do not reduce antihypertensives if diastolic BP falls <80 mmHg 3
• Do not use diuretics routinely—they further reduce plasma volume which is already contracted in preeclampsia 3

Postpartum Considerations

• Continue magnesium sulfate for 24-48 hours postpartum in severe cases 8, 9
• Continue antihypertensive therapy as needed postpartum
• Preeclampsia is a risk factor for developing cardiovascular disease later in life and mandates long-term follow-up 5

Transfer and Coordination

For severe preeclampsia, consider transfer to specialized obstetric center 3:

• Initiate magnesium sulfate and blood pressure control prior to transport
• Coordinate with obstetric and anesthetic-intensivist teams at receiving facility
• Involve emergency medical assistance service for medicalized transport