Safety of hormonal contraceptives in obesity
Use of combined hormonal contraception (combined oral contraceptives [COCs] or the contraceptive vaginal ring) in individuals with a body mass index (BMI) of 30 to 34 kg/m2 is considered safe (UKMEC 2). Their use in those with a BMI more than 35 kg/m2 requires expert judgment or referral (UKMEC 3), particularly if they have other cardiovascular risk factors.
Safety concerns for individuals with obesity using combined hormonal contraception are related to the effects of estrogen on cardiovascular risk (including VTE, acute myocardial infarction and stroke). Users of combined hormonal contraception who are obese are at further increased risk of VTE (including a possible higher risk of cerebral venous thrombosis) compared to users who are of normal weight. It is unknown whether obesity increases the risk of ischaemic stroke and myocardial infarction in users of combined hormonal contraception.