What are the diagnostic criteria for postpartum pre-eclampsia?

Diagnosing Postpartum Preeclampsia

Postpartum preeclampsia is diagnosed by new-onset hypertension (≥140/90 mmHg) occurring 48 hours to 6 weeks after delivery, accompanied by either proteinuria (≥0.3g/24h or protein/creatinine ratio ≥30 mg/mmol) or evidence of maternal organ dysfunction. 1, 2

Diagnostic Criteria

Essential Components

• Blood pressure measurement: Systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg confirmed on two separate occasions at least 15 minutes apart 1
• Timing: Occurring between 48 hours and 6 weeks postpartum in a previously normotensive woman 2
• Proteinuria assessment: One of the following:
  • Protein/creatinine ratio ≥30 mg/mmol (0.3 mg/mg) 3
  • 24-hour urine protein ≥300 mg 1
  • Dipstick ≥1+ (requires confirmation with quantitative methods) 1

Alternative Diagnostic Criteria (in absence of proteinuria)

New-onset hypertension with any of these signs of end-organ damage:

• Renal dysfunction: Serum creatinine ≥1.1 mg/dL or doubling of baseline 1
• Liver involvement: Elevated transaminases ≥2 times upper limit of normal 1
• Neurological complications: Severe headache, visual disturbances, eclampsia 1
• Hematological abnormalities: Thrombocytopenia <100,000/microliter 1
• Pulmonary edema 1

Diagnostic Approach

Initial Assessment

• Measure blood pressure at least every 4 hours while awake for at least 3 days postpartum 3, 4
• Perform urinalysis for protein assessment if hypertension is detected 1
• Screen for symptoms: headache, visual disturbances, epigastric pain, nausea/vomiting 1, 2

Laboratory Evaluation

• Complete blood count (focusing on platelet count) 1
• Comprehensive metabolic panel (liver enzymes, creatinine, electrolytes) 1
• Urine protein quantification (protein/creatinine ratio or 24-hour collection) 1, 5

Important Considerations

• An albumin-creatinine ratio <30 mg/mmol reliably excludes significant proteinuria 1
• Spot urine protein-to-creatinine ratio is an acceptable alternative to 24-hour collection as a "rule-out" test 5
• Urine dipstick alone is insufficient for diagnosis and requires confirmation 1, 5

Severe Features Requiring Immediate Attention

• Systolic BP ≥160 mmHg or diastolic BP ≥110 mmHg 1
• Persistent neurological symptoms (severe headache, visual changes) 1, 2
• Epigastric/right upper quadrant pain 2
• Pulmonary edema 1
• Progressive laboratory abnormalities 1

Common Pitfalls to Avoid

• Delayed recognition: Most women with postpartum preeclampsia present within 7-10 days after delivery, typically with neurological symptoms 2
• Inadequate monitoring: Women with preeclampsia risk factors should be monitored closely during the early postpartum period 4
• Relying solely on proteinuria: Proteinuria is not required for diagnosis if other features of organ dysfunction are present 1, 5
• Premature discharge: Women with gestational hypertension should not be discharged early (before 24 hours) to ensure adequate monitoring 4

Follow-up Recommendations

• All women with postpartum preeclampsia should be reviewed at 3 months to ensure BP, urinalysis, and laboratory abnormalities have normalized 3, 4
• Women still requiring antihypertensive medications at discharge should be reviewed within 1 week 4
• Additional check-ups at 7-14 days and 6 weeks postpartum are recommended 4
• Persistent abnormalities at 3 months require further investigation for underlying conditions 4

Risk Factors to Consider

• Previous preeclampsia (RR 7.19) 1
• Presence of antiphospholipid antibodies (RR 9.72) 1
• Pre-existing diabetes (RR 3.56) 1
• Multiple pregnancy (RR 2.93) 1
• Nulliparity (RR 2.91) 1
• Family history of preeclampsia (RR 2.90) 1
• Advanced maternal age ≥40 years (RR 1.68-1.96) 1
• Elevated BMI at booking (RR 1.55) 1
• Black race, cesarean delivery 2