Cardiovascular risk and combined oral contraceptives: clinical decisions in settings of uncertainty

Although generally safe, combined oral contraceptives (COCs) are associated with risks, including an estimated 2-fold increased relative risk of cardiovascular events. For most women taking COCs for contraception, absolute cardiovascular risks are very low, and the overall risks of COCs are outweighed by the risks of unwanted pregnancy. Nonetheless, risks of COCs may be excessive in some women, and both the American College of Obstetricians (ACOG) and the World Health Organization (WHO) have offered contraindications for COC use. Complicating this issue, COCs are commonly used for reasons other than contraception (eg, polycystic ovary syndrome, which is associated with subfertility and cardiovascular risk factors). Thus, in some clinical scenarios, ACOG and WHO guidelines may offer incomplete guidance regarding whether COC use would be associated with an unacceptable risk-benefit ratio. We propose that cardiovascular risk calculators may be helpful in some patients, as an adjunct to ACOG and WHO guidelines, by allowing physicians to estimate the attributable risk of COC-related cardiovascular events.