Table 6.
Relative risk of venous thromboembolism in current users of combined oral contraceptives according to length of use and with non-users of hormonal contraception as reference
| Product type | Women years | No of events* | Adjusted relative risk† (95% CI) | |||
|---|---|---|---|---|---|---|
| <3 months | 3-12 months | >1-4 years | >4 years | |||
| Non-use | 4 960 730 | 1812 | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
| Progestogen with 30-40 μg ethinylestradiol: | ||||||
| Levonorgestel (all) | 210 221 | 167 | 4.07 (2.70 to 6.15) | 2.54 (1.80 to 3.59) | 2.12 (1.61 to 2.80) | 1.88 (1.45 to 2.43) |
| Norgestimate | 267 664 | 165 | 3.81 (2.60 to 5.58) | 2.98 (2.22 to 4.00) | 2.47 (1.91 to 3.20) | 1.82 (1.27 to 2.59) |
| Desogestrel | 170 249 | 201 | 4.59 (3.01 to 7.00) | 4.20 (3.11 to 5.67) | 3.77 (2.95 to 4.81) | 4.64 (3.64 to 5.92) |
| Gestodene | 668 355 | 738 | 4.83 (3.85 to 6.05) | 4.65 (3.96 to 5.45) | 4.12 (3.61 to 4.70) | 3.94 (3.43 to 4.54) |
| Drospirenone | 286 859 | 266 | 4.70 (3.45 to 6.40) | 5.95 (4.88 to 7.24) | 3.38 (2.69 to 4.24) | 4.34 (3.10 to 6.08) |
| Cyproterone | 120 934 | 109 | 4.23 (2.50 to 7.17) | 4.21 (2.95 to 6.01) | 4.90 (3.70 to 6.49) | 2.43 (1.41 to 4.19) |
| Progestogen with 20 μg ethinylestradiol: | ||||||
| Desogestrel | 470 982 | 322 | 3.18 (2.31 to 4.38) | 3.18 (2.55 to 3.98) | 3.49 (2.91 to 4.17) | 3.09 (2.42 to 3.96) |
| Gestodene | 472 118 | 321 | 3.46 (2.49 to 4.81) | 4.51 (3.69 to 5.52) | 3.38 (2.81 to 4.06) | 2.65 (2.00 to 3.51) |
| Drospirenone | 23 055 | 23 | 6.16 (2.76 to 13.77) | 7.25 (4.19 to 12.56) | 2.58 (0.96 to 6.89) | — |
*Events are venous thromboembolisms.
†Adjusted for age, calendar year, and level of education.