Table 2. American College of Chest Physicians risk factors for venous thromboembolism.

Major risk factors
Immobility (strict bed rest for > 1 week in the antepartum period)
Post-partum hemorrhage > 1 L with surgery
Previous venous thromboembolism event
Pre-eclampsia with fetal growth restriction
Thrombophilia
Antithrombin
Factor V Leiden (homozygous or heterozygous)
Prothrombin G20210A (homozygous or heterozygous)
Medical conditions
Systemic lupus erythematosus
Heart disease
Sickle cell disease
Blood transfusion
Post-partum infection
Minor risk factors
Body mass index > 30 kg/m2
Multiple gestation
Post-partum hemorrhage > 1 L
Smoking > 10 cigarettes/day
Fetal growth restriction
Thrombophilia
Protein C deficiency
Protein S deficiency
Pre-eclampsia