Oral contraceptives and venous thromboembolism

More than 100 million women use the oral contraceptive pill worldwide.1 Many types of pill are available—26 types are listed in the British National Formulary—and the choice of which one to use is important to the women who use them and their doctors. Two linked studies assess the risk of venous thromboembolism in women taking the combined oral contraceptive.2 3

All oral contraceptives are effective in preventing pregnancy if they are taken correctly, so the choice of which one to use rests on the profile of side effects. Venous thromboembolism is one of the most serious side effects, and although it is rare, it can cause death (in about 1-2% of all cases of venous thromboembolism in women taking the pill).

Van Hylckama Vlieg and colleagues (doi:10.1136/bmj.b2921) present a case-control study from six anticoagulation clinics in the Netherlands, and Lidegaard …