Can signs of pulmonary embolism (PE) overlap with common symptoms of pregnancy?

Signs of Pulmonary Embolism Can Overlap with Pregnancy Symptoms

Yes, signs and symptoms of pulmonary embolism (PE) significantly overlap with normal physiological changes of pregnancy, making accurate clinical diagnosis notoriously difficult. 1 This overlap is a major reason why PE is a leading cause of pregnancy-related mortality in developed countries, accounting for approximately 20% of maternal deaths in the United States. 1, 2

Overlapping Symptoms and Diagnostic Challenges

• Common overlapping symptoms include:

  • Shortness of breath
  • Tachycardia
  • Leg swelling
  • Fatigue

• More specific PE symptoms that may help differentiate:

  • Pleuritic chest pain (absence has a negative predictive value of 97.8%) 3
  • Cough
  • Sweating 2

• Diagnostic challenges:

  • VTE is ultimately confirmed in less than 10% of pregnant women who present with concerning clinical features 1
  • Hormonal changes during pregnancy affect coagulation factors, increasing factors II, VII, and X by the third trimester 2
  • Decreased levels of coagulation inhibitor proteins further increase risk 2

Risk Assessment and Initial Evaluation

• The modified Wells score with a cutoff of ≥6 points is considered the most appropriate scoring system for evaluating suspected PE in pregnancy 2
• The pregnancy-adapted YEARS algorithm is a promising risk stratification method that is safe and effective 4
• Risk factors to consider:
  • History of DVT (odds ratio of 9.4) 2
  • Cesarean section (increases PE risk 20-fold compared to vaginal delivery) 2
  • Smoking (statistically significant association with PE) 3
  • Multiple risk factors present simultaneously 3

Diagnostic Approach

When PE is suspected in a pregnant woman:

1. Assess hemodynamic stability immediately

   • Perform bedside echocardiography if unstable 2

2. Chest X-ray (CXR) as first radiation-associated procedure 2

3. Based on CXR results:

   • If normal: Lung scintigraphy (V/Q scan) recommended over CTPA 1, 2
   • If abnormal: CTPA with low-radiation dose protocol 2

4. Consider bilateral compression ultrasound if DVT symptoms are present 2

5. Initiate anticoagulation while awaiting diagnostic results if clinical suspicion is high and bleeding risk is low 2

Important Considerations

• Currently available clinical and laboratory tools alone are not adequate to exclude PE in pregnancy 3
• D-dimer testing shows statistically significant differences between those with and without PE, but not to a clinically useful degree 3
• Arterial blood gas measurements have limited diagnostic value 3

Radiation Exposure Comparison

Modality	Maternal Breast Radiation Exposure	Lung Tissue Radiation Exposure
V/Q scan	0.98-1.07 mGy	5.7-13.5 mGy
CTPA	10-60 mGy	39.5 mGy

Pitfalls to Avoid

• Do not delay imaging due to radiation concerns - both V/Q and CTPA are considered safe in pregnancy 4
• Do not rely solely on clinical assessment to rule out PE in pregnant patients 3
• Do not withhold anticoagulation when clinical suspicion is high while awaiting diagnostic results 2
• Do not use NOACs (non-vitamin K antagonist oral anticoagulants) during pregnancy 2

Given the significant overlap between PE symptoms and normal pregnancy changes, combined with the potentially fatal consequences of missed diagnosis, imaging is justified when PE is suspected in pregnant patients.