What is the initial management of preeclampsia?

Preeclampsia: Comprehensive Guide for Step 1

Definition and Diagnosis

Preeclampsia is defined as new-onset hypertension (≥140/90 mmHg) after 20 weeks of gestation with either proteinuria OR evidence of end-organ damage. 1, 2

• Hypertension threshold: Systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg 3, 4
• Proteinuria: ≥300 mg/24 hours OR protein/creatinine ratio ≥30 mg/mmol (0.3 mg/mg) 3, 1
• Important update: Proteinuria is no longer required for diagnosis if end-organ damage is present 4
• End-organ damage includes: Renal insufficiency, liver involvement (elevated transaminases >2x normal), neurological complications (headache, visual disturbances), hematological complications (thrombocytopenia <100,000/μL), or fetal growth restriction 1, 4

Epidemiology and Risk Factors

• Incidence: Affects 3-7% of all pregnancies 3, 5, 6
• High-risk factors: Advanced maternal age, obesity, nulliparity, multi-fetal pregnancy, chronic hypertension, diabetes, renal disease, previous preeclampsia 7
• Mortality: Second leading cause of maternal mortality worldwide 3

Pathophysiology

Preeclampsia is a two-stage disease process:

1. Stage 1 (Placental): Defective trophoblast invasion leads to impaired spiral artery remodeling, causing placental hypoperfusion and ischemia 4, 7
2. Stage 2 (Maternal): The ischemic placenta releases factors causing generalized maternal endothelial dysfunction, leading to multisystem organ damage 4

Screening and Prevention

Screening Protocol

All pregnant women should undergo blood pressure screening at every prenatal visit throughout pregnancy. 3

• Frequency: BP measurements at every prenatal visit 3
• Risk assessment: Should be performed at booking and throughout pregnancy 3

Prevention for High-Risk Women

Low-dose aspirin (75-162 mg/day) should be initiated before 16 weeks' gestation (definitely before 20 weeks) in women with strong clinical risk factors. 8, 2

• Calcium supplementation: 1.2-2.5 g/day if dietary intake is low (<600 mg/day) 8, 2

Clinical Presentation and Severity Criteria

Severe Features (Any of the following)

All cases of preeclampsia should be considered potentially severe as they can rapidly progress to emergencies. 1, 2

• Severe hypertension: BP ≥160/110 mmHg 1, 8, 4
• Thrombocytopenia: Platelets <100,000/μL 4, 9
• Liver dysfunction: Transaminases >2x normal, epigastric or right upper quadrant pain 4, 9
• Renal insufficiency: Creatinine elevation, oliguria 4
• Neurological symptoms: Severe headache (independent risk factor for eclampsia), visual disturbances, altered mental status 3, 4
• Pulmonary edema 4, 9
• HELLP syndrome: Hemolysis, Elevated Liver enzymes, Low Platelets 4
• Fetal growth restriction or non-reassuring fetal status 3, 4

Critical Warning Signs

• Headache: Independent risk factor for eclampsia in preeclamptic women 3
• Epigastric pain and vomiting: Independent risk factors for serious morbidity in severe preeclampsia 3
• Fetal compromise: Can be the first clinical indication of preeclampsia 3

Initial Management Algorithm

Step 1: Hospitalization and Assessment

All women with newly diagnosed preeclampsia should be hospitalized initially to confirm diagnosis, assess severity, and monitor progression. 8, 2

Step 2: Maternal Monitoring

• Blood pressure: Every 4 hours (more frequently if severe features present) 8, 2
• Clinical assessment: Deep tendon reflexes, clonus, neurological symptoms 1, 8
• Pulse oximetry 1

Step 3: Laboratory Assessment

Obtain comprehensive laboratory evaluation immediately:

• CBC: Hemoglobin and platelet count 1
• Comprehensive metabolic panel: Liver enzymes (AST, ALT), creatinine, uric acid 1
• Urinalysis and protein/creatinine ratio 1
• Frequency: At least twice weekly for ongoing monitoring 8, 2

Step 4: Fetal Assessment

• Initial ultrasound: Fetal biometry, amniotic fluid volume, umbilical artery Doppler 1, 8
• Electronic fetal monitoring: Assess fetal heart rate and variability 1
• Serial surveillance: Ongoing monitoring based on severity 8, 2

Blood Pressure Management

Severe Hypertension (≥160/110 mmHg)

Severe hypertension requires urgent treatment in a monitored setting within minutes to prevent maternal stroke. 1, 8, 2

First-line agents (choose one):

1. Oral nifedipine: 10 mg, repeat every 20 minutes to maximum 30 mg 8, 2
2. IV labetalol: 20 mg bolus, then 40 mg after 10 minutes if needed, followed by 80 mg every 10 minutes to maximum 220 mg 8, 2
3. IV hydralazine: Alternative option 1, 8

Target BP: Systolic 110-140 mmHg, diastolic 85 mmHg 1, 8, 2

Critical Contraindications

• Avoid sublingual nifedipine: Risk of precipitous BP drops causing myocardial infarction or fetal distress 8
• Never combine IV magnesium with calcium channel blockers: Risk of myocardial depression 8
• ACE inhibitors are absolutely contraindicated: Cause fetal renal dysgenesis in second and third trimesters 8

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

• Oral antihypertensives: Target diastolic BP 85 mmHg, systolic 110-140 mmHg 8, 2

Seizure Prophylaxis with Magnesium Sulfate

Magnesium sulfate should be administered for seizure prophylaxis in women with preeclampsia who have severe hypertension or neurological symptoms. 1, 8, 2

Dosing Regimen (FDA-approved)

For severe preeclampsia or eclampsia:

• Loading dose: 4-5 g IV in 250 mL D5W or NS infused over 3-4 minutes, OR 10 g IM (5 g in each buttock) 10
• Maintenance: 4-5 g IM into alternate buttocks every 4 hours OR 1-2 g/hour continuous IV infusion 8, 10
• Duration: Continue until delivery and for 24 hours postpartum 8, 10
• Therapeutic level: 2.5-7.5 mEq/L (optimal for seizure control is 6 mg/100 mL) 10

Monitoring and Toxicity

• Monitor: Patellar reflexes, respiratory rate, urine output 10
• Toxicity signs: Deep tendon reflexes disappear at ~10 mEq/L, respiratory paralysis may occur at this level, heart block can occur 10
• Antidote: IV calcium gluconate 3
• Maximum dose: 30-40 g/24 hours (20 g/48 hours in severe renal insufficiency) 10

Critical Warning

Continuous maternal administration beyond 5-7 days can cause fetal skeletal demineralization, osteopenia, and neonatal fractures. 10

Fluid Management

Strictly limit total fluid intake to 60-80 mL/hour to prevent pulmonary edema. 8, 2

• Goal: Euvolemia 8, 2
• Avoid "running dry": Increases acute kidney injury risk 8, 2
• Diuretics are contraindicated: Further reduce plasma volume 8
• Plasma volume expansion is not recommended routinely 1, 2

Timing of Delivery

Delivery is the definitive treatment for preeclampsia. 8, 2, 9

Delivery Indications by Gestational Age

≥37 weeks:

• Immediate delivery indicated for all women with preeclampsia 1, 8, 2

34-37 weeks:

• Deliver if severe features present 4, 9
• Expectant management acceptable without severe features 1

<34 weeks:

• Administer corticosteroids for 48 hours for fetal lung maturation 8, 4
• Consider expectant management in select cases with close monitoring 9

Mandatory Immediate Delivery (Any Gestational Age)

Deliver immediately if any of the following occur:

• Uncontrolled severe hypertension despite treatment with 3 antihypertensive classes 1, 8, 2
• Eclampsia (seizures) 9
• Pulmonary edema 1, 9
• Oxygen saturation <90% 1
• Progressive deterioration: Liver function, renal function, hemolysis, or platelet count 1, 2
• Neurological complications: Stroke, cortical blindness 4, 9
• Placental abruption 1, 8, 9
• Non-reassuring fetal status 1, 8, 2

Important Caveats

• Neither serum uric acid nor level of proteinuria should be used as indication for delivery 1, 2
• Blood pressure alone is not a reliable indicator of disease severity 1
• Eclampsia can occur with relatively mild hypertension: 34% of eclamptic women had maximum diastolic BP ≤100 mmHg 3

Postpartum Management

Close monitoring must continue for at least 3 days postpartum as eclampsia can still develop. 8, 2

• BP monitoring: Every 4-6 hours while awake 8, 2
• Continue magnesium sulfate: For 24 hours postpartum 8, 10
• Antihypertensives: Continue and taper slowly after days 3-6 postpartum 8, 2
• Follow-up: Review within 1 week if still requiring antihypertensives 2
• 3-month postpartum visit: BP, urinalysis, and labs should normalize; persistent abnormalities require further investigation 2

Long-term Implications

Women with history of preeclampsia have significantly increased lifetime cardiovascular risk. 2, 4

• Increased risks: Cardiovascular disease, stroke, diabetes mellitus, venous thromboembolism, chronic kidney disease 2, 4
• Counseling: All women should be informed of these risks 8, 2
• Long-term follow-up: Mandatory for cardiovascular risk assessment 4

Common Pitfalls to Avoid

Critical errors in preeclampsia management:

• Failure to assess or act on risk factors at booking 3
• Failure to act on signs and symptoms after 20 weeks' gestation 3
• Attempting to distinguish "mild" vs "severe" clinically: All cases may rapidly become emergencies 2
• Using proteinuria level or uric acid to guide delivery decisions 1, 2
• Inadequate monitoring of women with warning symptoms (headache, epigastric pain, visual changes) 3
• Delaying delivery in presence of maternal end-organ dysfunction 4, 9
• Administering magnesium sulfate beyond 5-7 days in pregnancy 10

Anesthetic Considerations

• Neuraxial analgesia/anesthesia: First-line technique in absence of thrombocytopenia 4
• General anesthesia concerns: Airway edema and intubation-induced BP elevation 4