What labs are checked for postpartum hypertension?

Laboratory Tests for Postpartum Hypertension

For postpartum hypertension, essential laboratory tests include a complete blood count, comprehensive metabolic panel with liver enzymes, serum creatinine, uric acid, and urinalysis with protein-to-creatinine ratio to assess for end-organ damage and guide management decisions. 1

Core Laboratory Tests

• Complete blood count (CBC) - Hemoglobin and platelet count are essential, as thrombocytopenia (<100,000/mm³) indicates severity and potential HELLP syndrome 1, 2
• Liver function tests - AST, ALT, LDH to detect liver involvement, which may indicate preeclampsia or HELLP syndrome 1, 2
• Renal function assessment:
  • Serum creatinine and electrolytes to evaluate kidney function 1
  • Serum uric acid, which correlates with worse maternal and fetal outcomes when elevated 1, 2
• Urinalysis and protein assessment:
  • Urinalysis with microscopy to evaluate for proteinuria and hematuria 1
  • Protein-to-creatinine ratio (PCR) or albumin-to-creatinine ratio (ACR) to quantify proteinuria 1

Monitoring Frequency

• Initial laboratory panel should be performed at diagnosis to establish baseline values 2, 3
• For women with abnormal values before delivery, repeat hemoglobin, platelets, creatinine, and liver enzymes the day after delivery and then every second day until stable 3
• For ongoing monitoring, minimum twice-weekly blood tests are recommended for women with preeclampsia 2
• More frequent testing is required with clinical deterioration or changes in maternal condition 2, 3

Additional Tests Based on Clinical Presentation

• For severe hypertension or suspected secondary causes:

  • Renal ultrasound if serum creatinine or urine testing is abnormal 1
  • Echocardiography if heart failure is suspected (may present with pulmonary edema) 1
  • NT-proBNP if heart failure is suspected (note: may be elevated in preeclampsia without cardiac abnormality) 1
  • Imaging studies (CT or MRI) if neurological symptoms are present 1

• For suspected secondary hypertension:

  • Free plasma metanephrines if pheochromocytoma is suspected 1
  • Additional tests based on clinical suspicion may include imaging of adrenals or renal arteries 1

Clinical Pitfalls to Avoid

• Do not use uric acid levels alone as an indication for delivery timing 2
• Avoid using proteinuria levels in isolation to determine management decisions 2
• Do not underestimate the importance of monitoring in the first week postpartum, as blood pressure typically peaks 3-7 days after delivery 1
• Inadequate monitoring frequency may miss disease progression - twice weekly laboratory testing is recommended for those with preeclampsia 2
• Do not fail to educate patients about when to seek medical attention for elevated blood pressure (systolic >140 mmHg or diastolic >90 mmHg) 4

Home Monitoring Considerations

• Home blood pressure monitoring is recommended for postpartum patients with hypertension 1
• Women with hypertensive disorders of pregnancy should be educated about thresholds for seeking medical attention (systolic BP >140 mmHg or diastolic BP >90 mmHg) 4
• Successful postpartum home monitoring programs recommend checking BP daily or twice daily in the first week after discharge 1

By following this comprehensive laboratory assessment approach, clinicians can effectively monitor for complications of postpartum hypertension and make timely management decisions to reduce maternal morbidity and mortality.