Preeclampsia

Early Identification & Evidence-Based Management

MFM Clinical Update 2025

Epidemiology & Impact

• 2–8% of pregnancies in the United States
• Leading cause of maternal morbidity and mortality worldwide
• Disproportionate burden: Black women 60% higher risk
• Associated with preterm birth, IUGR, placental abruption
• Long-term cardiovascular risk for mother and offspring

ACOG Practice Bulletin #222, 2020

Pathophysiology

• Stage 1 (Early pregnancy): Abnormal placentation
  • Inadequate trophoblast invasion
  • Failure of spiral artery remodeling
• Stage 2 (Mid-late pregnancy): Maternal syndrome
  • Endothelial dysfunction (↓ VEGF, ↑ sFlt-1, ↑ sEng)
  • Systemic inflammation and oxidative stress
  • Hypertension and end-organ damage

sFlt-1/PlGF ratio increasingly used for diagnosis and prediction

Diagnostic Criteria (ACOG 2019)

Blood Pressure

SBP ≥140 or DBP ≥90 mmHg on two occasions at least 4 hours apart after 20 weeks in previously normotensive woman

Plus ONE of:

• Proteinuria ≥300 mg/24h or protein/creatinine ≥0.3
• Thrombocytopenia (platelets <100,000)
• Renal insufficiency (Cr >1.1 or doubling of baseline)
• Elevated liver enzymes (2× upper limit)
• Pulmonary edema
• New-onset headache or visual symptoms

Preeclampsia with Severe Features

• Severe hypertension: SBP ≥160 or DBP ≥110 mmHg
• Thrombocytopenia: Platelets <100,000/μL
• Liver dysfunction: Transaminases 2× normal, RUQ pain
• Renal dysfunction: Creatinine >1.1 mg/dL or doubling
• Pulmonary edema
• Cerebral or visual symptoms: Persistent headache, scotomata

Severe features warrant closer monitoring and earlier delivery

Risk Stratification

High-Risk Factors (>8% risk)

• Prior preeclampsia (especially <34 weeks)
• Multifetal gestation
• Chronic hypertension
• Type 1 or 2 diabetes
• Renal disease
• Autoimmune disease (SLE, APS)

Moderate-Risk Factors

Nulliparity, obesity (BMI >30), family history, age ≥35, prior adverse pregnancy outcome, IVF, low socioeconomic status

First-Trimester Screening

FMF Algorithm (11-13+6 weeks)

• Maternal characteristics + history
• Mean arterial pressure (MAP)
• Uterine artery Doppler (pulsatility index)
• Serum PAPP-A and PlGF

Detection rate: ~75% for early preeclampsia (<37 weeks) with 10% false positive rate

ASPRE trial demonstrated effectiveness of this approach

Aspirin Prophylaxis

USPSTF & ACOG Recommendations (2021)

• Dose: 81-162 mg daily (consider 162 mg for high-risk)
• Timing: Initiate before 16 weeks (ideally 12 weeks)
• Continue until delivery
• Indication: ≥1 high-risk factor OR ≥2 moderate-risk factors

NNT: 72 to prevent one case of preeclampsia

ASPRE trial: 62% reduction in early preeclampsia with 150mg at bedtime

Antenatal Surveillance

Preeclampsia Without Severe Features

• BP monitoring 2× weekly (can be outpatient)
• Weekly labs (CBC, LFTs, creatinine)
• Fetal testing: NST/BPP 1-2× weekly starting at diagnosis
• Growth ultrasound every 3 weeks

Preeclampsia With Severe Features

• Inpatient management at ≥34 weeks
• Consider expectant management 23-33+6 weeks at tertiary center
• Daily labs, continuous or frequent BP monitoring
• Daily fetal testing

Acute Severe Hypertension Management

Goal: SBP 140-150 mmHg, DBP 90-100 mmHg within 30-60 minutes

First-Line Agents

ACOG recommends treating sustained SBP ≥160 or DBP ≥110 mmHg

Magnesium Sulfate for Seizure Prophylaxis

Indications

• Preeclampsia with severe features
• During labor and 24-48 hours postpartum
• Treatment and prevention of eclamptic seizures

Dosing

Loading: 4-6 g IV over 15-20 minutes

Maintenance: 2 g/hour continuous infusion

Monitoring

• Deep tendon reflexes (discontinue if absent)
• Respiratory rate >12/min
• Urine output >25 mL/hour
• Serum magnesium levels if renal insufficiency (goal 4-7 mEq/L)

Timing of Delivery

Betamethasone recommended <34 weeks; consider up to 36+6 weeks

HELLP Syndrome

Diagnostic Criteria

• Hemolysis (↑ LDH, ↑ bilirubin, ↓ haptoglobin, schistocytes)
• Elevated Liver enzymes (AST/ALT >2× normal)
• Low Platelets (<100,000/μL)

Management

• 10-20% may present without hypertension or proteinuria
• Delivery indicated at ≥34 weeks
• Consider dexamethasone if <34 weeks and expectant management attempted
• Monitor for DIC, liver hematoma/rupture, acute renal failure

Postpartum Management

Immediate Postpartum (0-72 hours)

• Continue magnesium sulfate 24-48 hours
• Monitor BP closely (peaks 3-6 days postpartum)
• Treat severe hypertension aggressively
• Monitor for postpartum preeclampsia/eclampsia

Preferred Antihypertensives

• Labetalol, nifedipine (safe for breastfeeding)
• Avoid methyldopa (slow onset), ACE-I/ARBs (use with caution in breastfeeding)

NSAIDs

Use with caution; may worsen hypertension and renal function

Long-Term Cardiovascular Risk

• 2-4× increased risk of cardiovascular disease
• 2× increased risk of stroke
• Risk of chronic hypertension, metabolic syndrome, diabetes
• Earlier age of cardiovascular events (40s-50s)

Postpartum Counseling

• Discuss long-term cardiovascular risk
• Recommend BP check at 7-10 days, 6 weeks, and annually
• Lifestyle modifications: diet, exercise, weight management
• Consider cardiology referral for early preeclampsia or recurrent disease

AHA 2021: Preeclampsia is independent CV risk factor

Recurrence Risk & Future Pregnancy

Preconception Counseling

• Optimize chronic conditions
• Aspirin prophylaxis starting <16 weeks
• Consider first-trimester screening
• Enhanced surveillance in subsequent pregnancy

Clinical Pearls

• Diagnosis doesn't require proteinuria – other end-organ findings sufficient
• Headache + hyperreflexia doesn't predict seizure; magnesium still indicated
• BP can normalize between readings; don't dismiss diagnosis
• Platelets often first to fall – trend labs serially
• Postpartum hypertension peaks days 3-6, not immediately after delivery
• Delivery is curative for fetus, but maternal disease may progress 48-72h

Summary & Clinical Action Items

• Screen early: Risk stratify at first prenatal visit
• Prevent when possible: Aspirin <16 weeks for high-risk patients
• Diagnose accurately: New hypertension + end-organ involvement
• Manage severe features: Control BP, give MgSO4, deliver appropriately
• Time delivery correctly: Balance maternal/fetal risks
• Follow long-term: Counsel on cardiovascular risk, ensure ongoing care

Evidence-based care can significantly reduce maternal morbidity and improve outcomes