Makindo Medical Notes

Related Subjects: | Assessing Breathlessness | Pulmonary Embolism | Deep Vein Thrombosis | DVT/PE in Pregnancy | CTPA

📖 Introduction

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

• RCOG GTG-37a: Reducing the Risk of VTE in Pregnancy & Puerperium
• NICE NG89: VTE Diagnosis and Management