Pregnancy increases incidence of deep vein thrombosis and venous thromboembolic disease (0.5–2/1,000 pregnancies).
- Incidence highest postpartum:
- Increased 2- to 5-fold for deep vein thrombosis
- Increased 15-fold for pulmonary embolism
- Cesarean section increases risk even further:
- Two-fold increase compared with vaginal delivery
- Delivery of placenta results in large surge of procoagulants
- Surgical intervention increases endothelial injury
- Smoking (>1/2 ppd) may increase risk for endothelial injury
|Changes in coagulation|
- Coagulation factors increase, protein S and C activity decreases, antifibrinolytics increase
- Patients with inherited thrombophilias are at increased risk (factor V Leiden, protein S or C deficiency, AT-III deficiency, antiphospholipid antibody)
- Chorioamnionitis may increase risk
- Compression by enlarged uterus (L > R)
- Proximal and pelvic vein thrombosis more common
- Obesity, bed rest, multiple gestation are additional risk factors
- Prior history of thromboembolic disease
- Preexisting thrombophilias
- Swelling of lower extremity is common in pregnancy
- Left-sided thrombosis in >80% of cases
- Common during pregnancy and after Cesarean section
|Radiographic evaluation||Venous thrombosis in lower extremities and pelvis||Venous compression Doppler US||Highly sensitive and specific for proximal vein thrombosis|
- May help when Doppler US is equivocal
- Suspected pelvic vein thrombus
|Contrast venography||“Gold standard,” seldom done|
|Pulmonary vasculature||V/Q scan||Superior test if CXR Normal|
- Test of choice with abnormal chest x-ray
- If V/Q scan is equivocal
- Inadequate sensitivity for subsegmental emboli
|Indicated in all patients with|
- One or more episode of venous thromboembolism in the past
- Antiphospholipid syndrome
- Homozygous prothrombin mutation
- Homozygous factor V Leiden mutation
- Coexisting heterozygosity for prothrombin and factor V Leiden mutations
- Protein S deficiency
- Protein C deficiency
|Cesarean section in patients with no additional risk factors is not an indication for thromboprophylaxis|
|One risk factor||Graduated compression stockings or pneumatic compression device or pharmacologic thromboprophylaxis|
|Multiple risk factors||Graduated compression stockings or pneumatic compression device and pharmacologic thromboprophylaxis|
- Enoxaparin 40 mg q day or BID
- Dalteparin 5,000 U Q day or BID
- Tinzaparin 4,500 U Q day
|Some recommend therapeutic doses in patients with past history of multiple DVT|
|Heparin (unfractionated; SQ)|
- 5,000 U BID
- Adjusted dose: start with 5,000 U BID and titrate to anti-Xa activity (therapeutic if anti-Xa is 0.1–0.3 U/mL); usual range is 5,000–10,000 U twice daily. Measure anti-Xa 6 h after every other dose
|Some recommend therapeutic doses in patients with past history of multiple venous thromboembolism|
- Start after heparin; overlap for at least 5 days
- Therapeutic range: INR 2–3
|Warfarin does not get excreted in breast milk in significant amounts|
- Usually started 6 hours after Cesarean delivery unless there is concern for ongoing ...
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