| Risk Factor | Number of cases (%), (N=173) | Risk Factor | Number of cases (%), (N=173) |
| Age (≥ 50yr) | 10 (5.8%) | Hypothyroidism | 2 (1.2%) |
| Surgery | 5 (2.9%) | Atherosclerosis | 1 (0.6%) |
| Trauma | 2 (1.2%) | Varicose veins | 1 (0.6%) |
| Liver disease | 2 (1.2%) | Infection | 1 (0.6%) |
| Congenital heart disease | 1 (0.6%) | Intrauterine hypoxia | 1 (0.6%) |
| Obesity | 10 (5.8%) | Positive family history | 2 (1.2%) |
| Smoking | 7 (4%) | Positive previous history of VTE | 3 (1.7%) |
| Pregnancy | 57 (33%) | Combination of 2 risk factors | 17 (9.8%) |
| Post-partum | 2 (1.2%) | Combination of 3 risk factors | 2 (1.2%) |
| OCP/HRT | 3 (1.7.%) | No risk factors | 30 (17%) |
| Malignancy | 2 (1.2%) | Unknown (not documented) | 42 (24%) |