How do you diagnose postpartum preeclampsia?

Diagnosing Postpartum Preeclampsia

Postpartum preeclampsia should be diagnosed in women with new-onset hypertension occurring between 48 hours to 6 weeks after delivery, accompanied by at least one feature of end-organ dysfunction, after excluding other etiologies. 1

Definition and Timing

Postpartum preeclampsia is characterized by:

• New-onset hypertension (≥140/90 mmHg) after delivery
• Occurs most commonly within the first 7-10 days postpartum 1
• May develop in women with no prior history of hypertension during pregnancy (55% of cases) 2

Diagnostic Algorithm

Step 1: Blood Pressure Measurement

• Confirm hypertension: SBP ≥140 mmHg or DBP ≥90 mmHg
• Classify severity: Mild (140-159/90-109 mmHg) or Severe (≥160/110 mmHg) 3
• Monitor BP at least every 4 hours while awake for at least 3 days postpartum 3

Step 2: Assess for End-Organ Dysfunction

Look for at least one of the following:

1. Proteinuria:

   • Screen with automated dipstick urinalysis
   • Confirm with urine protein/creatinine ratio ≥30 mg/mmol (0.3 mg/mg) 3

2. Neurological symptoms:

   • Headache (most common presenting symptom) 2, 1
   • Visual disturbances/scotomata
   • Hyperreflexia or clonus
   • Altered mental status
   • Seizures (eclampsia)

3. Laboratory abnormalities:

   • Complete blood count: Thrombocytopenia (<100,000/μL)
   • Liver function tests: Elevated transaminases (AST, ALT)
   • Renal function: Elevated serum creatinine
   • Elevated uric acid 3

4. Other manifestations:

   • Right upper quadrant/epigastric pain
   • Pulmonary edema
   • HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets)

Step 3: Exclude Other Causes

Rule out alternative diagnoses such as:

• Primary seizure disorder
• Cerebral hemorrhage
• Drug use
• Sepsis
• Thrombotic thrombocytopenic purpura

Diagnostic Workup

1. Laboratory tests:

   • Complete blood count with platelets
   • Comprehensive metabolic panel (liver enzymes, creatinine, electrolytes)
   • Uric acid level
   • LDH and haptoglobin (if hemolysis suspected)
   • Urinalysis and protein/creatinine ratio 3

2. Additional tests (based on presentation):

   • Fundoscopy
   • EKG
   • Brain imaging (CT or MRI) if severe headache, visual changes, or neurological symptoms
   • Echocardiography if heart failure or chest pain present 3

High-Risk Populations

Women with higher risk for postpartum preeclampsia include those with:

• Older maternal age
• Black race
• Obesity
• History of cesarean delivery 1
• Severe preeclampsia during pregnancy
• Early-onset preeclampsia during pregnancy 4

Clinical Pearls and Pitfalls

1. Key pitfall: Assuming women without antepartum preeclampsia cannot develop postpartum preeclampsia. Over half of postpartum preeclampsia cases occur in women with no prior diagnosis during pregnancy 2.

2. Warning: Headache is the most common prodromal symptom before seizures. All women with postpartum headaches should have their blood pressure checked 2.

3. Caution: Not all women will present with the "classic" features. Some may have only mild hypertension with other symptoms 2.

4. Important: Eclamptic seizures may develop for the first time in the early postpartum period, even in women who did not have preeclampsia during pregnancy 3.

5. Monitoring: Women with preeclampsia should be considered at high risk for complications for at least 3 days postpartum and require close monitoring 3.

By following this systematic approach to diagnosis, postpartum preeclampsia can be identified promptly, allowing for timely intervention to prevent serious maternal complications.