Table 2: Risk points, each corresponding to a five-fold increased risk, are added, yielding a risk score.

1 point2 points3 points>4 points5Very high risk6

Heterozygote FV LeidenProt S deficiencyHomo FV LeidenPrior VTEMechanical heart prosthesis
Heterozygote FII mutProt C deficiencyHomo FII mutAPS without VTE7Chronic warfarin prophylaxis
Overweight1Immobilization4Antithrombin deficiency
Cesarean SectionRecurrent VTE
Heredity for VTE2APS with VTE7
Age >40 years
Preeclampsia
Hyperhomocysteinemia3
Abruptio placenta
Inflammatory bowel disease
Other major riskfactor

Homo: Homozygote, mut: mutation, VTE: venous thrombembolism.
APS: Antiphospholipidsyndrome, Prot: protein, FV: faktor V, FII: factor II (prothrombin).
1Overweight = (BMI >28 in early pregnancy).
2VTE in first-degree relative <60 years of age.
3Homocysteine >8 μmol/L in pregnancy.
4During cast treatment for fracture or strict bed rest short-term thromboprophylaxis is recommended.
5Women with prior VTE or APS without VTE have risk score 4 independent of other risk factors.
6Women in this group are classified as “very high risk” and are not scored.
7Women with APS are recommended low dose (75 mg) acetylsalicylic acid in addition to LMWH.
The risk score is formed by adding each point to a score between 0 and maximum 4 (for >4 points).