Diagnosing Postpartum Preeclampsia
Postpartum preeclampsia should be diagnosed through monitoring blood pressure at least every 4-6 hours for the first 3 days postpartum, along with assessment of proteinuria, maternal symptoms, and laboratory tests to evaluate organ function. 1
Definition and Timing
Postpartum preeclampsia is defined as new-onset hypertension with proteinuria or other systemic manifestations occurring from 48 hours up to 6 weeks after delivery 2. Most cases present within the first 7-10 days postpartum 2, with the median presentation being around 5 days after delivery 3.
Diagnostic Algorithm
Step 1: Blood Pressure Measurement
- Monitor BP at least every 4-6 hours during the day for at least 3 days postpartum 1
- Ensure proper technique when measuring blood pressure (errors have been implicated in maternal deaths) 1
- Diagnostic criteria: Systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg 1
- Severe hypertension: Systolic BP ≥160 mmHg or diastolic BP ≥110 mmHg 1
Step 2: Proteinuria Assessment
- Perform automated dipstick urinalysis for screening 1
- If positive, quantify with urine protein/creatinine ratio
- Significant proteinuria: ≥30 mg/mmol (0.3 mg/mg) 1
Step 3: Evaluate for Maternal Symptoms and Signs
Common presenting symptoms include 3, 2:
- Headache (most common neurological symptom)
- Visual disturbances/changes
- Epigastric or right upper quadrant pain
- Shortness of breath or chest pain
- Edema (face, hands, legs)
- Altered mental status
Step 4: Laboratory Assessment
Order the following tests 1:
- Complete blood count (focusing on hemoglobin and platelets)
- Liver function tests (AST, ALT)
- Renal function tests (creatinine)
- Uric acid levels (associated with worse maternal and fetal outcomes)
Step 5: Rule Out Other Causes
Consider and exclude other potential causes of symptoms and hypertension:
- Retained placental products 1
- Other neurological conditions (if headache or seizures present)
- Other causes of liver or kidney dysfunction
Important Clinical Considerations
Over half of postpartum preeclampsia cases (55%) have no history of preeclampsia during pregnancy 3, making vigilant monitoring essential for all postpartum women.
Not all women will present with all classic features of preeclampsia (hypertension, proteinuria, edema, hyperreflexia) 3.
Continuous BP monitoring may be more reliable than intermittent monitoring for detecting sustained severe-range blood pressure in postpartum patients with preeclampsia 4.
Avoid NSAIDs for postpartum analgesia in women with preeclampsia unless other analgesics are not working, especially if they have renal disease, placental abruption, acute kidney injury, or other risk factors for renal impairment 1.
All women should be reviewed at 3 months postpartum to ensure BP, urinalysis, and laboratory tests have normalized. If proteinuria or hypertension persists, further investigation is required 1.
Management Implications of Diagnosis
When postpartum preeclampsia is diagnosed:
- Continue or initiate antihypertensive therapy 1
- Consider magnesium sulfate for seizure prophylaxis if severe features are present 2
- Monitor closely for at least 3 days postpartum 1
- Taper antihypertensives slowly after days 3-6 postpartum unless BP becomes low (<110/70 mmHg) 1
Follow-up After Diagnosis
- Women requiring antihypertensives at discharge should be reviewed within 1 week 1
- All women should be reviewed at 3 months postpartum 1
- Counsel about increased long-term cardiovascular risks and need for annual medical review 1
By following this systematic approach to diagnosis, postpartum preeclampsia can be identified promptly, allowing for timely intervention to reduce maternal morbidity and mortality.