What are the management guidelines for preeclampsia?

Management of Preeclampsia

Initial Assessment and Hospitalization

All women with newly diagnosed preeclampsia should be hospitalized initially to confirm diagnosis, assess severity, and monitor disease progression. 1, 2

• Preeclampsia is diagnosed by new-onset hypertension (≥140/90 mmHg) after 20 weeks of gestation with either proteinuria (≥300 mg/24h or protein/creatinine ratio ≥30 mg/mmol) or evidence of end-organ damage 1
• Proteinuria is no longer absolutely required for diagnosis if end-organ dysfunction is present 3
• Blood pressure should be measured every 4 hours, more frequently if severe features are present 1, 2
• Laboratory monitoring should include complete blood count with platelets, liver enzymes (AST/ALT), serum creatinine, and uric acid at least twice weekly 1, 2
• Initial fetal assessment must include ultrasound with fetal biometry, amniotic fluid volume, and umbilical artery Doppler 4, 1

Blood Pressure Management

Severe Hypertension (≥160/110 mmHg)

Severe hypertension requires urgent treatment within 15 minutes in a monitored setting to prevent maternal cerebral hemorrhage. 1, 5

• First-line IV therapy is labetalol: 20 mg IV bolus, then 40 mg after 10 minutes if needed, followed by 80 mg every 10 minutes to maximum total dose of 220 mg 1, 5
• Alternative IV options include nicardipine or hydralazine 5
• Oral nifedipine can be used: 10 mg, repeat every 20 minutes to maximum 30 mg 1
• Target blood pressure is systolic 110-140 mmHg and diastolic 85 mmHg (or at minimum <160/105 mmHg) 1, 2, 5
• The goal is to decrease mean BP by 15-25% to prevent cerebral hemorrhage while maintaining uteroplacental perfusion 5

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

• Treat with oral antihypertensives aiming for diastolic BP of 85 mmHg and systolic BP between 110-140 mmHg 1

Medications to Absolutely Avoid

• ACE inhibitors, ARBs, and direct renin inhibitors are absolutely contraindicated due to severe fetotoxicity and renal dysgenesis 1, 2, 5
• Sublingual nifedipine should be avoided due to risk of precipitous blood pressure drops 1
• Do not combine IV magnesium with calcium channel blockers due to myocardial depression risk 1
• Sodium nitroprusside should only be used as last resort for extreme emergencies due to risk of fetal cyanide poisoning 5

Seizure Prophylaxis with Magnesium Sulfate

Magnesium sulfate must be administered to all women with severe preeclampsia or severe hypertension to prevent eclamptic seizures. 1, 2, 5

• Loading dose: 4-5 g IV over 5 minutes 5, 6
• Maintenance dose: 1-2 g/hour continuous IV infusion 5, 6
• Alternative regimen: 4 g IV loading dose followed by 4-5 g IM into alternate buttocks every 4 hours 6
• Continue for 24 hours postpartum 1, 6
• Therapeutic serum magnesium level is 4-7.5 mEq/L; levels of 6 mg/100 mL are optimal for seizure control 6
• Do not continue magnesium sulfate beyond 5-7 days as it can cause fetal abnormalities 6

Critical Monitoring During Magnesium Therapy

• Monitor deep tendon reflexes before each dose; reflexes disappear at plasma levels approaching 10 mEq/L 6
• Monitor respiratory rate continuously; respiratory paralysis may occur at levels ≥10 mEq/L 6
• Urine output must be monitored hourly via Foley catheter with target ≥100 mL/4 hours or >35 mL/hour 1, 5
• Oxygen saturation should be monitored continuously (maternal early warning if <95%) 2, 5
• Have calcium gluconate available as antidote for magnesium toxicity 6
• In severe renal insufficiency, maximum dosage is 20 grams/48 hours with frequent serum magnesium monitoring 6

Fluid Management

Strictly limit total fluid intake to 60-80 mL/hour to prevent pulmonary edema. 4, 1, 2

• Aim for euvolemia; avoid "running dry" as this increases acute kidney injury risk 1
• Diuretics are absolutely contraindicated in preeclampsia as they further reduce plasma volume 1, 2
• For pulmonary edema, use IV nitroglycerin starting at 5 mcg/min, gradually increased every 3-5 minutes to maximum 100 mcg/min 5
• Plasma volume expansion is not recommended routinely 5

Fetal Monitoring

• Perform fetal biometry, amniotic fluid volume assessment, and umbilical artery Doppler at first diagnosis 4, 1
• Repeat ultrasound every 2 weeks if initial assessment is normal, more frequently if fetal growth restriction is present 4, 2, 5
• Continuous fetal heart rate monitoring should be performed for severe preeclampsia 2
• Serial umbilical artery Doppler studies should be performed to assess placental function 2

Timing of Delivery

Delivery is the definitive treatment for preeclampsia. 1, 2

Gestational Age ≥37 Weeks

• Deliver immediately after maternal stabilization 2, 5
• Induction of labor is associated with improved maternal outcomes 5

Gestational Age 34-37 Weeks

• Deliver at 37 weeks for preeclampsia without severe features 2
• Deliver after 34 weeks for severe preeclampsia 3
• Expectant conservative management is appropriate if maternal and fetal status remain stable 5

Gestational Age <34 Weeks

• Administer corticosteroids for fetal lung maturation (48-hour course) 4, 2
• Conservative expectant management at a center with Maternal-Fetal Medicine expertise 5
• Magnesium sulfate should be administered for fetal neuroprotection before 32 weeks 4

Absolute Indications for Immediate Delivery (Any Gestational Age)

• Repeated episodes of severe hypertension despite treatment with 3 classes of antihypertensives 1, 5
• Progressive thrombocytopenia or progressively abnormal liver/renal function tests 5
• Pulmonary edema 5
• Severe intractable headache, repeated visual scotomata, or convulsions 5
• Non-reassuring fetal status 1, 5
• Placental abruption 1, 5
• Maternal pulse oximetry deterioration 5
• HELLP syndrome with severe features 5

Special Consideration for Early Gestational Age

• For gestational age <24 weeks, expectant management is associated with high maternal morbidity with limited perinatal benefit—counsel regarding pregnancy termination 5

Recognition of Severe Features and HELLP Syndrome

Severe Preeclampsia Criteria

• Blood pressure ≥160/110 mmHg 3
• Thrombocytopenia <100,000/μL 3
• Liver transaminases above twice normal values 3
• Renal insufficiency (serum creatinine >1.1 mg/dL or doubling of baseline) 3
• Pulmonary edema 3
• New-onset cerebral or visual disturbances 3
• Persistent epigastric or right upper quadrant pain 3

HELLP Syndrome Recognition

• HELLP syndrome is defined by hemolysis, elevated liver enzymes, and low platelets with maternal mortality rate of 3.4% 5
• Epigastric or right upper quadrant pain is a hallmark symptom suggesting hepatic capsule distension 5
• Monitor for severe hypoglycemia intraoperatively 5

Postpartum Management

Close monitoring must continue for at least 72 hours postpartum as eclampsia can still develop. 1, 2

• Monitor blood pressure at least every 4 hours while awake 1, 2
• Continue magnesium sulfate for 24 hours postpartum 2, 6
• Continue antihypertensives and taper slowly after days 3-6 postpartum 1
• Most cases of eclampsia occur within 48 hours postpartum, but can occur up to 4 weeks later 7

Prevention Strategies for High-Risk Women

Low-dose aspirin (75-162 mg/day) should be initiated before 16 weeks' gestation (ideally before 20 weeks) for women with high-risk factors. 1, 2

High-Risk Factors Warranting Aspirin Prophylaxis

• History of preeclampsia (relative risk 7.19) 4
• Chronic hypertension 2
• Type 1 or 2 diabetes (relative risk 3.56) 4
• Renal disease 2
• Autoimmune disease (especially antiphospholipid antibodies with relative risk 9.72) 4
• Multifetal gestation (relative risk 2.93) 4

Additional Prevention Measures

• Supplemental calcium (1.2-2.5 g/day) if dietary intake is low (<600 mg/day) 4, 1
• Calcium at a dose of at least 1 g/d reduces preeclampsia likelihood in women with low calcium intake 4
• Exercise using an ACOG program guideline (aerobic exercise for 50 minutes, 3× per week) has been associated with reduced gestational hypertension and preeclampsia 4
• Vitamin C and E supplementation are not recommended and may be associated with worse pregnancy outcomes 4

Risk Assessment Early in Pregnancy

Women should be assessed for risk factors before 20 weeks and referred for specialist input if they have specific high-risk criteria. 4

Criteria for Early Specialist Referral (Before 20 Weeks)

• Previous preeclampsia 4
• Multiple pregnancy 4
• Pre-existing hypertension or booking diastolic BP ≥90 mmHg 4
• Pre-existing renal disease or booking proteinuria 4
• Pre-existing diabetes 4
• Presence of antiphospholipid antibodies 4
• Any two other risk factors including: nulliparity (relative risk 2.91), family history of preeclampsia (relative risk 2.90), age ≥40 years (relative risk 1.68-1.96), raised BMI at booking (relative risk 1.55), or pregnancy interval ≥10 years 4

Long-Term Counseling and Follow-Up

• Women with a history of preeclampsia have significantly increased lifetime risk of cardiovascular disease, stroke, and venous thromboembolism 1, 2
• Risk of recurrent preeclampsia in future pregnancies is approximately 15%, with an additional 15% risk of gestational hypertension 2
• Regular blood pressure monitoring by a primary care physician is recommended 2
• Women should be counseled about increased cardiovascular risk and need for long-term follow-up 1

Critical Pitfalls to Avoid

• Do not attempt to diagnose "mild versus severe" preeclampsia clinically—all cases may become emergencies rapidly 5
• Do not use serum uric acid or level of proteinuria as indication for delivery 5
• Do not reduce antihypertensives if diastolic BP falls <80 mmHg 5
• Do not delay treatment of severe hypertension—treatment must begin within 15 minutes 1, 5
• Do not continue magnesium sulfate beyond 5-7 days in pregnancy due to fetal abnormality risk 6
• Failure to identify and act on known risk factors at booking and failure to recognize signs and symptoms from 20 weeks' gestation are common preventable errors 4