The largest study to date of risks associated with hormonal contraceptives finds that all such products raise risk of thrombotic stroke and myocardial infarction (MI).
Risks of thrombotic strike and MI are increased with OCs containing EE.
Differences in risks associated with progestin type are small.
The largest study to date of risks associated with hormonal contraceptives finds that all such products raise risk of thrombotic stroke and myocardial infarction (MI). How much higher the risk depends on the method and type of birth control a woman is using and the amount of hormones it contains.
Some 3,311 thrombotic strokes and 1,725 MIs were reported in the 15-year Danish historical cohort study that involved more than 1.6 million nonpregnant women aged 15 to 49 with no history of heart disease or cancer. The results were published in The New England Journal of Medicine.
The relative risks (RR) of stroke and MI were 1.5 and 1.3, respectively, for women currently using oral contraceptives (OCs) containing 30 to 40 µg ethinyl estradiol (EE) and norgestimate, increasing to 2.2 and 2.3, respectively, for pills that also contained norethindrone. The RRs for pills containing levonorgestrel, desogestrel, drospirenone, and gestodene fell somewhat in the middle of those extremes.
Similarly, RRs for stroke and MI were 0.9 and 0.0, respectively, for OCs containing EE and drospirenone, compared with 1.7 and 1.2, respectively, for
EE/gestodene combinations, and 1.5 and 1.6, respectively, for EE/desogestrel combinations.
Risk of stroke was more than tripled in users of the transdermal patch, but it was not associated with increased risk of MI. These findings, however, were based on a smaller group of women, and thus, could have been due to chance. RRs for both stroke and MI were more than doubled in users of the vaginal ring (2.5 and 2.1, respectively).
Neither the implant nor the progestin-only intrauterine device were associated with an increased risk of stroke or MI, but again, the number of women using these devices in the study was small.
Risks of stroke and MI in individual women-particularly young ones-remain low, say the study’s authors. And once the women stopped using hormonal contraception, their risks returned to those of never-users.
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