Table 2.
Exposure time, number of events of venous thromboembolism, crude incidence per 10 000 user years, and adjusted relative risk of venous thromboembolism in current users of different oral contraceptives and hormone releasing intrauterine device with non-users as reference group
| Group | Women years | No of events* | Crude incidence per 10 000 user years* | Adjusted relative risk† (95% CI) |
|---|---|---|---|---|
| Non-use | 4 960 730 | 1812 | 3.7 | 1 (reference) |
| Progestogen with 50 μg ethinylestradiol: | ||||
| Norethisterone | 6848 | 11 | 16.1 | 5.66 (3.12 to 10.3) |
| Levonorgestrel | 23 691 | 31 | 13.1 | 3.54 (2.48 to 5.05) |
| Progestogen with 30-40 μg ethinylestradiol: | ||||
| Norethisterone | 27 355 | 10 | 3.7 | 1.57 (0.84 to 2.92) |
| Phasic levonorgestrel | 105 970 | 89 | 8.4 | 2.28 (1.85 to 2.83) |
| Levonorgestrel combined | 104 251 | 78 | 7.5 | 2.19 (1.74 to 2.75) |
| Norgestimate | 267 664 | 165 | 6.2 | 2.56 (2.18 to 3.01) |
| Desogestrel | 170 249 | 201 | 11.8 | 4.21 (3.63 to 4.87) |
| Gestodene | 668 355 | 738 | 11.0 | 4.23 (3.87 to 4.63) |
| Drospirenone | 286 859 | 266 | 9.3 | 4.47 (3.91 to 5.11) |
| Cyproterone | 120 934 | 109 | 9.0 | 4.10 (3.37 to 4.99) |
| Progestogen with 20 µg ethinylestradiol: | ||||
| Desogestrel | 470 982 | 322 | 6.8 | 3.26 (2.88 to 3.69) |
| Gestodene | 472 118 | 321 | 6.8 | 3.50 (3.09 to 3.97) |
| Drospirenone | 23 055 | 23 | 10.0 | 4.84 (3.19 to 7.33) |
| Progestogen only: | ||||
| Norethisterone | 44 168 | 9 | 2.0 | 0.56 (0.29 to 1.07) |
| Desogestrel | 29 187 | 6 | 2.1 | 0.64 (0.29 to 1.42) |
| Levonorgestrel releasing intrauterine device | 155 149 | 55 | 3.5 | 0.83 (0.63 to 1.08) |
*Events are venous thromboembolisms.
†Adjusted for age, year, and level of education.