In this 15-year Danish historical cohort study, we followed nonpregnant women, 15 to 49 years old, with no history of
cardiovascular disease or
cancer. Data on use of
hormonal contraception, clinical end points, and potential confounders were obtained from four national registries.
RESULTS: A total of 1,626,158 women contributed 14,251,063 person-years of observation, during which 3311
thrombotic strokes (21.4 per 100,000 person-years) and 1725
myocardial infarctions (10.1 per 100,000 person-years) occurred. As compared with nonuse, current use of
oral contraceptives that included
ethinyl estradiol at a dose of 30 to 40 μg was associated with the following relative risks (and 95% confidence intervals) for
thrombotic stroke and
myocardial infarction, according to
progestin type:
norethindrone, 2.2 (1.5 to 3.2) and 2.3 (1.3 to 3.9);
levonorgestrel, 1.7 (1.4 to 2.0) and 2.0 (1.6 to 2.5);
norgestimate, 1.5 (1.2 to 1.9) and 1.3 (0.9 to 1.9);
desogestrel, 2.2 (1.8 to 2.7) and 2.1 (1.5 to 2.8);
gestodene, 1.8 (1.6 to 2.0) and 1.9 (1.6 to 2.3); and
drospirenone, 1.6 (1.2 to 2.2) and 1.7 (1.0 to 2.6), respectively. With
ethinyl estradiol at a dose of 20 μg, the corresponding relative risks according to
progestin type were as follows:
desogestrel, 1.5 (1.3 to 1.9) and 1.6 (1.1 to 2.1);
gestodene, 1.7 (1.4 to 2.1) and 1.2 (0.8 to 1.9); and
drospirenone, 0.9 (0.2 to 3.5) and 0.0. For transdermal patches, the corresponding relative risks were 3.2 (0.8 to 12.6) and 0.0, and for a
vaginal ring, 2.5 (1.4 to 4.4) and 2.1 (0.7 to 6.5).
CONCLUSIONS: