Diagnostic Approach for Suspected Pulmonary Embolism in Pregnant Patients

Initial Assessment and Risk Stratification

In pregnant patients with suspected pulmonary embolism (PE), especially those with a history of previous PE, a structured diagnostic approach is essential as PE is a leading cause of pregnancy-related mortality in developed countries 1
The American College of Chest Physicians recommends that pregnant patients with symptoms such as shortness of breath and tachycardia, but normal oxygen saturation, require prompt evaluation, particularly given their history of PE 2, 3
Despite normal oxygen saturation, tachycardia in a pregnant patient with previous PE history should raise suspicion for recurrent PE, according to the European Society of Cardiology 2

The American Thoracic Society recommends evaluating for signs and symptoms of deep vein thrombosis (DVT) as this would guide the initial diagnostic approach, with a strength of evidence rated as high 1, 4
If signs/symptoms of DVT are present, bilateral compression ultrasound (CUS) of lower extremities should be performed first, as recommended by the American College of Chest Physicians 4
A chest X-ray should be the first radiation-associated procedure in the imaging workup for suspected PE in pregnancy, with a strong recommendation based on the need to minimize radiation exposure, according to the American College of Radiology 1, 4

If the chest X-ray is normal, lung scintigraphy (V/Q scan) is recommended as the next imaging test rather than computed tomography pulmonary angiography (CTPA), with a moderate strength of evidence, according to the European Respiratory Society 1, 4
If the chest X-ray is abnormal, CTPA is recommended as the next imaging test, with a high strength of evidence, according to the European Society of Cardiology 4, 5

D-dimer testing is not recommended to exclude PE in pregnant women as pregnancy normally increases D-dimer levels, leading to false positives, according to the American College of Obstetricians and Gynecologists 1, 4
Modern imaging techniques for PE diagnosis during pregnancy expose the fetus to radiation doses well below thresholds associated with complications (50-100 mSv), with a low strength of evidence, according to the European Society of Radiology 5
Both V/Q scan and CTPA are considered safe during pregnancy when properly performed, with a moderate strength of evidence, according to the American College of Radiology 3, 6

If PE is confirmed, low-molecular-weight heparin (LMWH) is the treatment of choice during pregnancy, with a high strength of evidence, according to the American Heart Association 5, 6
Novel oral anticoagulants (NOACs) are contraindicated during pregnancy, with a high strength of evidence, according to the European Society of Cardiology 6
Anticoagulant treatment should be administered for at least 6 weeks after delivery with a minimum overall treatment duration of 3 months, with a moderate strength of evidence, according to the American College of Chest Physicians 6