Postcaesarean Venous Thromboembolism

Postcaesarean venous thromboembolism is clot in the deep veins of the legs or pelvis, with or without spread to the lungs, after caesarean section. The risk is 2 to 4 times higher than after vaginal birth and peaks in the first 2 weeks, with risk persisting for 6 weeks. It is a leading cause of maternal death and needs prompt anticoagulation.

• Risk factors: emergency caesarean section, body mass index above 30 kg/m2, age above 35 years, preeclampsia, postpartum haemorrhage, infection, immobility, previous clot, thrombophilia, sickle cell disease.
• Left leg and iliofemoral veins are most often involved.
• Prophylaxis lowers risk by about two thirds.

Women have leg swelling, pain, warmth and tenderness, or breathlessness, pleuritic chest pain, cough, haemoptysis, palpitations and collapse. Fever and tachycardia are common.

• Unilateral calf circumference difference of 2 cm or more.
• Respiratory rate above 20 per minute and low oxygen saturation in embolism.
• Differential diagnosis: wound or pelvic infection, cellulitis, muscle strain, pneumonia, peripartum cardiomyopathy, amniotic fluid embolism, atelectasis, septic pelvic thrombophlebitis.
• Complications: pulmonary embolism, post-thrombotic syndrome, recurrence, bleeding on treatment, heparin-induced thrombocytopenia, maternal death.

The approach is clinical probability with compression ultrasound and lung imaging.

• Compression ultrasound of the leg veins (repeat at 3 to 7 days if negative and suspicion remains).
• For suspected pulmonary embolism: oxygen saturation, ECG, chest X-ray, then CT pulmonary angiography; D-dimer is raised after birth and is not reliable.
• Full blood count, platelets, creatinine, liver enzymes and coagulation screen before heparin.
• Echocardiography and troponin for severity in suspected massive embolism.

The principle is prevention in every woman at risk and full dose anticoagulation for confirmed clot.

• Supportive: early mobilisation; hydration; graduated compression stockings of 20 to 30 mmHg; leg elevation; oxygen to keep saturation above 94 percent for embolism; breastfeeding continues.
• Pharmacological: prophylaxis: enoxaparin 40 mg subcutaneous daily starting 6 to 12 hours after surgery for 10 days (6 weeks if high risk); weight bands: 20 mg below 50 kg, 60 mg for 91 to 130 kg, 80 mg for 131 to 170 kg, 0.6 mg/kg above 170 kg; treatment: enoxaparin 1 mg/kg subcutaneous 12-hourly for at least 3 months; unfractionated heparin 80 units/kg IV bolus then 18 units/kg/hour adjusted to an aPTT of 1.5 to 2.5 times control for massive embolism or creatinine clearance below 30 mL/minute; warfarin 5 mg oral daily from day 1 with enoxaparin overlap for at least 5 days until the INR is 2 to 3 for 24 hours; alteplase 10 mg IV bolus then 90 mg over 2 hours for shock; paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours); no direct oral anticoagulants in breastfeeding.
• Procedures: inferior vena cava filter if anticoagulation is contraindicated; catheter or surgical embolectomy for failed thrombolysis.
• Special groups: renal impairment (creatinine clearance below 30 mL/minute) uses unfractionated heparin, or enoxaparin 1 mg/kg subcutaneous once daily for treatment (20 mg once daily for prophylaxis) with anti-Xa monitoring; platelets falling by 50 percent after day 5 of heparin suggest heparin-induced thrombocytopenia and need specialist anticoagulation; antiphospholipid syndrome needs warfarin or full dose enoxaparin.
• Red flags: breathlessness, chest pain, haemoptysis, syncope, systolic blood pressure below 90 mmHg, bleeding, severe headache.
• Follow-up: platelets at day 7 to 14 on heparin; review at 1 week and 6 weeks; thrombophilia testing at 3 months; plan prophylaxis in future pregnancy.