What is the workup and treatment for a pregnant woman diagnosed with preeclampsia?

Workup and Treatment for Preeclampsia

All women with newly diagnosed preeclampsia should be hospitalized initially for assessment, and delivery at 37 weeks or beyond is the definitive treatment, with earlier delivery indicated for severe features or maternal/fetal compromise. 1, 2, 3

Initial Diagnostic Workup

Blood Pressure Assessment

• Confirm hypertension with BP ≥140/90 mmHg on repeat measurements 1, 4
• Measure BP every 4 hours while awake (more frequently if severe features present) 1, 3
• Home BP monitoring is a useful adjunct for ongoing management 1

Proteinuria Evaluation

• Screen with automated dipstick urinalysis, then quantify positive results with urine protein/creatinine ratio 1
• A ratio ≥30 mg/mmol (0.3 mg/mg) is abnormal 1
• Repeat assessments if proteinuria not initially present 1

Laboratory Testing

• Obtain at least twice weekly: complete blood count with hemoglobin and platelets, liver transaminases (AST/ALT), serum creatinine, and uric acid 1, 3, 4
• These tests assess for progression to severe features including thrombocytopenia, hepatic dysfunction, and renal impairment 1
• Increase frequency if clinical deterioration occurs 3, 4

Fetal Assessment

• Perform initial ultrasound for fetal biometry, amniotic fluid volume, and umbilical artery Doppler 1, 3, 4
• Repeat ultrasound every 2 weeks if initial assessment normal, more frequently if fetal growth restriction present 1, 3
• Continuous or intermittent electronic fetal heart rate monitoring to assess fetal well-being 2, 3, 4

Clinical Examination

• Assess for neurological signs including deep tendon reflexes and clonus 1, 4
• Evaluate for symptoms of severe features: severe headache, visual disturbances, epigastric/right upper quadrant pain 4

Blood Pressure Management

Severe Hypertension (≥160/110 mmHg)

• Requires urgent treatment within 15 minutes in a monitored setting 1, 3, 4
• First-line agents: oral nifedipine OR intravenous labetalol OR intravenous hydralazine 1, 3
• Oral labetalol may be used if these are unavailable 1
• Target BP: systolic 110-140 mmHg and diastolic 85 mmHg 1, 3, 4

Non-Severe Hypertension (≥140/90 mmHg)

• Treat consistently elevated BP to reduce likelihood of severe hypertension and complications 1
• Acceptable agents: oral methyldopa, labetalol, oxprenolol, or nifedipine 1
• Second or third-line agents: hydralazine and prazosin 1
• Reduce or cease antihypertensives if diastolic BP falls <80 mmHg 1

Critical Contraindications

• Never use ACE inhibitors, ARBs, or direct renin inhibitors due to severe fetotoxicity causing renal dysgenesis 3, 4
• Avoid diuretics as they further reduce plasma volume and worsen uteroplacental perfusion 3, 4

Magnesium Sulfate for Seizure Prophylaxis

Indications

• Administer to women with preeclampsia who have proteinuria with severe hypertension (≥160/110 mmHg) OR any neurological signs/symptoms 1, 2, 3
• All women with severe preeclampsia should receive magnesium sulfate 1, 3, 4

Dosing

• Loading dose: 4-5 g IV over 3-4 minutes OR 4 g IV plus 10 g IM (5 g in each buttock) 1, 5
• Maintenance: 1-2 g/hour by continuous IV infusion OR 4-5 g IM into alternate buttocks every 4 hours 1, 5
• Continue until paroxysms cease and for at least 24 hours postpartum 1, 3, 5
• Target serum magnesium level: 6 mg/100 mL (optimal for seizure control) 5

Monitoring During Magnesium Therapy

• Monitor patellar reflex (disappears at ~10 mEq/L), respiratory function, and urine output 1, 5
• Urine output should be ≥100 mL/4 hours or >35 mL/hour via Foley catheter 3
• Oxygen saturation should be monitored continuously (maternal early warning if <95%) 3
• Respiratory paralysis may occur at plasma levels approaching 10 mEq/L 5

Precautions

• Maximum total daily dose: 30-40 g in 24 hours 5
• In severe renal insufficiency, maximum is 20 g/48 hours with frequent serum magnesium monitoring 5
• Do not use continuously beyond 5-7 days as it can cause fetal abnormalities 5
• Have calcium gluconate available as antidote for magnesium toxicity 5

Fluid Management

• Strictly limit total fluid intake to 60-80 mL/hour to prevent pulmonary edema 3
• Plasma volume expansion is not recommended routinely 1

Delivery Timing and Indications

At or Beyond 37 Weeks

• Deliver immediately after maternal stabilization 1, 2, 3
• This applies to all preeclampsia regardless of severity at term 1, 2

Between 34-37 Weeks

• Consider delivery at 37 weeks for preeclampsia without severe features 1, 3
• Expectant conservative management may be appropriate between 34-37 weeks if stable 1

Before 34 Weeks

• Administer corticosteroids for fetal lung maturation (48-hour course) 3
• Expectant management possible in select women with severe preeclampsia before 32 weeks 6

Immediate Delivery Indications (Regardless of Gestational Age)

Deliver immediately if any of the following develop: 1, 2, 4

• Repeated episodes of severe hypertension despite maintenance treatment with 3 classes of antihypertensive agents
• Progressive thrombocytopenia
• Progressively abnormal renal or liver enzyme tests
• Pulmonary edema
• Abnormal neurological features (severe intractable headache, repeated visual scotomata, or eclamptic seizures)
• Nonreassuring fetal status

Important Caveats

• Neither serum uric acid level nor degree of proteinuria should be used as indications for delivery 1, 4
• Prefer vaginal delivery unless cesarean indicated for standard obstetric reasons 2

Postpartum Management

Immediate Postpartum Period (First 72 Hours)

• Consider women at high risk for preeclamptic complications for at least 3 days postpartum 1, 3
• Monitor BP and clinical condition at least every 4 hours while awake 1, 3
• Continue antenatal antihypertensives 1
• Continue magnesium sulfate for 24 hours postpartum 3
• Eclamptic seizures may develop for the first time in the early postpartum period 1

Analgesia Considerations

• Avoid NSAIDs unless other analgesics are not working, especially if renal disease, placental abruption, AKI, sepsis, or postpartum hemorrhage present 1, 4

Blood Pressure Management

• Treat any hypertension before day 6 postpartum 1
• Withdraw antihypertensive therapy slowly over days, never cease abruptly 1

Follow-Up at 3 Months

• Review all women at 3 months postpartum to ensure BP, urinalysis, and laboratory abnormalities have normalized 1
• If proteinuria or hypertension persists, initiate appropriate referral for further investigations 1

Long-Term Counseling and Prevention

Cardiovascular Risk

• Women with preeclampsia have significant long-term cardiovascular risks including cardiovascular disease, stroke, and venous thromboembolism 1, 3
• Annual medical review is advised lifelong 1
• Aim to achieve prepregnancy weight by 12 months and limit interpregnancy weight gain 1
• Adopt healthy lifestyle including exercise and eating well 1

Future Pregnancy Prevention

• For women with high-risk factors (prior preeclampsia, chronic hypertension, pregestational diabetes, BMI >30 kg/m², antiphospholipid syndrome, assisted reproduction), prescribe low-dose aspirin 75-162 mg/day 1, 3
• Initiate aspirin ideally before 16 weeks but definitely before 20 weeks gestation 1, 3
• Provide supplemental calcium 1.2-2.5 g/day if dietary intake likely <600 mg/day 1
• Low molecular weight heparin is NOT indicated for prevention 1, 4

Critical Pitfalls to Avoid

• Do not classify preeclampsia as "mild" versus "severe" clinically—all cases may become emergencies, often rapidly 1, 2
• Do not delay delivery at ≥37 weeks based on non-reactive NST or other fetal testing; delivery is indicated regardless 2
• Do not use blood pressure level alone to determine disease severity; serious organ dysfunction can develop at relatively mild BP elevations 4
• Do not routinely use PlGF or sFlt-1/PlGF ratio for rule-in or rule-out testing outside clinical trials 1
• Ensure management occurs in hospital with appropriate obstetrical care, maternal intensive care capabilities, and NICU for premature infants 4