Venous Thromboembolism Pregnancy and Puerperium
Related Subjects:
| Assessing Breathlessness
| Pulmonary Embolism
| Deep Vein Thrombosis
| DVT/PE in Pregnancy
| CTPA
VTE - including deep vein thrombosis (DVT) and pulmonary embolism (PE) - is the
leading cause of maternal death in the UK.
Pregnancy is a recognised hypercoagulable state, and the risk extends into the puerperium (first 6 weeks postpartum).
Early recognition and prompt treatment are critical to reduce maternal morbidity and mortality.
🧬 Pathophysiology
- Virchow’s triad in pregnancy:
- ↑ Venous stasis: gravid uterus compresses IVC & iliac veins (especially left side).
- ↑ Hypercoagulability: physiological rise in clotting factors (VII, VIII, X, fibrinogen) + reduced protein S.
- ↓ Fibrinolysis: protective against haemorrhage, but ↑ clot risk.
- Most pregnancy-associated DVTs involve the left iliofemoral vein.
- PE risk highest postpartum, particularly after C-section.
⚠️ Risk Factors
- Emergency > elective C-section.
- Prolonged immobility, hospitalisation, or surgery.
- Obesity, age >35, smoking.
- Thrombophilia (antithrombin deficiency, factor V Leiden, prothrombin mutation).
- Previous VTE, family history.
- Multiple pregnancy, pre-eclampsia, postpartum haemorrhage.
- Medical comorbidities (IBD, lupus, cancer, nephrotic syndrome).
🔎 Clinical Presentation
- DVT: Unilateral leg swelling, pain, tenderness, erythema (commonly left leg).
- PE: Sudden-onset dyspnoea, pleuritic chest pain, tachycardia, tachypnoea, haemoptysis.
- Severe PE: Syncope, hypotension, pulseless electrical activity (PEA) arrest.
- Beware: physiological breathlessness and pregnancy oedema can mimic PE/DVT.
🩺 Differentials
- Pregnancy-related: physiological oedema, anxiety, musculoskeletal pain.
- Cardiac: peripartum cardiomyopathy, myocarditis, ACS.
- Respiratory: pneumonia, asthma, pneumothorax.
- Obstetric: amniotic fluid embolism.
🧪 Investigations
- Wells score: ❌ Not validated in pregnancy.
- D-dimer: Not reliable - physiologically raised in pregnancy.
- Bloods: FBC, U&E, coagulation profile, group & save.
- ECG: Sinus tachycardia, RV strain, S1Q3T3 (nonspecific).
- CXR: Always do first → exclude pneumonia, pneumothorax.
- Compression ultrasonography (CUS): First-line for suspected DVT → safe, no radiation.
⚠️ May miss pelvic/iliac DVT.
- V/Q scan: Preferred if CXR normal and no lung disease.
- CTPA: Alternative to V/Q if CXR abnormal, unstable patient, or V/Q unavailable.
- Echocardiography: In unstable patients → RV strain suggests massive PE.
- Thrombophilia testing: Consider if strong FHx or recurrent events.
💊 Management
- Start therapeutic LMWH immediately if suspicion high - do not wait for imaging unless unsafe.
- LMWH is safe in pregnancy; adjust dose to maternal weight. Requires anti-Xa monitoring in some cases.
- Avoid: Warfarin (teratogenic), DOACs (insufficient data).
- Duration: Continue until at least 6 weeks postpartum and for a minimum of 3 months.
- Thrombolysis: Only for life-threatening PE (maternal arrest or massive PE).
- Delivery planning:
- Stop LMWH ≥24h before elective C-section or epidural.
- Restart 4–6h after vaginal delivery or 12h after C-section (if haemostasis secure).
- Postpartum: Warfarin may be used while breastfeeding (not teratogenic postnatally).
📊 Summary Table
|
|
| Aspect |
Pregnancy Consideration |
| Risk |
6× ↑ risk during pregnancy, persists until 6 weeks postpartum |
| First-line test (DVT) |
Compression ultrasonography (CUS) |
| First-line test (PE) |
CXR + V/Q scan (if CXR normal) or CTPA depending on context |
| Blood tests |
D-dimer not reliable; Wells score not validated |
| Initial treatment |
Start weight-adjusted LMWH immediately if suspected VTE |
| Avoid |
Warfarin (teratogenic in pregnancy), DOACs (not recommended) |
| Thrombolysis |
Only in life-threatening PE (massive PE or maternal collapse) |
| Duration |
Continue anticoagulation until ≥6 weeks postpartum (≥3 months total) |
📚 References
