What is the management of pulmonary embolism (PE) during pregnancy and puerperium?

Management of Pulmonary Embolism in Pregnancy and Puerperium

Immediate Anticoagulation

Low-molecular-weight heparin (LMWH) administered as therapeutic fixed doses based on early pregnancy weight is the definitive treatment for pulmonary embolism in pregnant women without hemodynamic instability, and must be continued throughout the entire pregnancy. 1, 2

• Initiate LMWH immediately upon clinical suspicion of PE while diagnostic workup proceeds, particularly in patients with high or intermediate clinical probability 1, 2
• Calculate dosing based on early pregnancy weight, not current weight, to avoid underdosing 1, 2
• NOACs (including apixaban, rivaroxaban, dabigatran, edoxaban) are absolutely contraindicated during pregnancy and lactation—if a patient presents on a NOAC, switch immediately to LMWH 1, 2, 3
• Unfractionated heparin (UFH) with weight-adjusted bolus may be used as an alternative, particularly when rapid reversal capability is needed or in high-risk PE requiring close titration 1, 2, 3

Diagnostic Approach

Perform formal diagnostic assessment with validated imaging methods without delay—radiation exposure from CT pulmonary angiography or V/Q scanning poses minimal fetal risk compared to the consequences of untreated PE. 1, 2

• Begin with chest radiograph as the first imaging study 3
• Proceed to CT pulmonary angiography (CTPA) or ventilation/perfusion (V/Q) lung scan based on availability and clinical context 1, 2
• Do not rely on D-dimer testing in pregnancy, as physiologic elevations during pregnancy reduce specificity 1, 2
• Do not use clinical prediction rules (PESI/sPESI) derived for non-pregnant patients, as pregnancy causes physiologic tachycardia, hypotension, and dyspnea that falsely elevate scores 1
• Consider compression ultrasonography of lower extremities if DVT symptoms present, as confirming DVT avoids radiation exposure 2, 3

Risk Stratification and Hemodynamic Instability

Stratify patients based on hemodynamic stability—those with hypotension, shock, or cardiac arrest constitute high-risk PE requiring immediate escalation beyond anticoagulation alone. 1, 2

High-Risk PE (Hemodynamic Instability)

• Systemic thrombolysis is the primary intervention for high-risk PE with hypotension or shock during pregnancy 1, 2, 3
• Alteplase is the most commonly used agent (67% of reported cases), though bleeding risk is approximately 18% during pregnancy 4, 5
• Surgical embolectomy or catheter-directed thrombolysis should be considered if systemic thrombolysis is contraindicated or fails 1, 6, 5
• Catheter-directed thrombolysis may be preferred over systemic thrombolysis as it uses lower thrombolytic doses and targets the clot directly 6, 5
• Maternal survival with thrombolysis approaches 94%, with fetal mortality around 12-20% 4, 5

Intermediate/Low-Risk PE (Hemodynamically Stable)

• LMWH alone is sufficient—do not routinely administer systemic thrombolysis 1, 2
• Monitor for clinical deterioration requiring escalation to rescue thrombolysis 1

Peripartum Management

Discontinue LMWH at the onset of regular uterine contractions or plan cessation 24 hours before scheduled delivery to minimize bleeding risk. 1, 3

• For high-risk PE near delivery, convert LMWH to UFH infusion at least 36 hours prior to anticipated delivery 2, 3
• Stop UFH infusion 4-6 hours before delivery to allow clearance 1, 2, 3
• Do not insert spinal or epidural needle within 24 hours of the last therapeutic LMWH dose 1, 2, 3
• Do not administer LMWH within 4 hours of epidural catheter removal 1, 3
• Verify activated partial thromboplastin time (aPTT) is normal before regional anesthesia if UFH was used 3
• Avoid thrombolysis at the time of delivery except in truly life-threatening PE with hemodynamic collapse, as postpartum bleeding risk reaches 58% 1, 3, 5

Duration of Anticoagulation

Continue anticoagulation for a minimum of 3 months total, with at least 6 weeks postpartum. 1, 2, 3

• Maintain LMWH throughout pregnancy until delivery 1, 2
• After delivery, transition to vitamin K antagonists (VKAs) if desired, as they are safe during breastfeeding 1, 2, 3
• VKAs can be given to breastfeeding mothers without risk to the infant 1, 2, 3
• Reassess at 3 months to determine need for extended anticoagulation based on provoked versus unprovoked PE 1

Multidisciplinary Coordination

Establish close collaboration between obstetrics, anesthesia, hematology, and the attending physician before discharge to coordinate labor planning and anticoagulation management. 1, 2, 3

• All pregnant patients with confirmed PE should be reviewed by a consultant before discharge 1
• Document clear responsibility for ongoing care and follow-up 1
• Plan timing of delivery and anticoagulation cessation in advance for high-risk cases 2, 3

Critical Pitfalls to Avoid

• Never use NOACs during pregnancy—this is the most common and dangerous error 1, 2, 3
• Never delay diagnostic imaging due to radiation concerns—fetal radiation exposure from CTPA or V/Q scan is minimal (0.003-0.13 mGy) and far safer than missing PE 1
• Never perform neuraxial anesthesia within 24 hours of therapeutic LMWH—epidural hematoma risk is unacceptable 1, 2, 3
• Never use thrombolysis peripartum unless the patient is dying from massive PE—postpartum hemorrhage risk is 58% versus 18% antepartum 3, 5
• Never dose LMWH based on current pregnancy weight—use early pregnancy weight to avoid underdosing as pregnancy progresses 1, 2
• Never use warfarin in first trimester or last 6 weeks of pregnancy—embryopathy and fetal bleeding risks are prohibitive 1