Cardiovascular disease and use of oral and injectable progestogen-only contraceptives and combined injectable contraceptives. Results of an international, multicenter, case-control study. World Health Organization Collaborative Study of Cardiovascular Disease and Steroid Hormone Contraception

Abstract

This report describes the first study to evaluate the risks of cardiovascular disease (CVD) associated with the use of oral and injectable progestogen-only and combined injectable contraceptives. Based on combined data from Africa, Asia, Europe, and Latin America collected in the World Health Organization (WHO) Collaborative Study, odds ratios (OR) for CVD combined, strokes, venous thromboembolism (VTE), and acute myocardial infarction (AMI) were calculated. Among 3697 CVD cases (59% stroke, 31% VTE, and 10% AMI), 53, 37, and 13 women, respectively, were current users of oral and injectable progestogen-only and combined injectable contraceptives. Overall, the adjusted OR for all CVD combined compared with nonusers of any type of steroid hormone contraceptive (SHC) associated with current use of oral and injectable progestogen-only contraceptives and combined injectable contraceptives, respectively, were 1.14 (95% CI: 0.79-1.63), 1.02 (0.68-1.54), and 0.95 (0.49-1.86). No significant changes in OR were apparent for strokes, VTE, or AMI in association with any of these types of contraception. However, a small, nonsignificant increase in OR for VTE was apparent in association with oral and injectable progestogen-only contraceptives. Among women with a history of hypertension, OR for stroke, as compared with that for nonusers of any type of SHC with no history of hypertension, rose from 7.2 (6.1-8.5) among nonusers of any type of SHC to 12.4 (4.1-37.6) among current users of all oral progestogens. Although limited by the small number of cases and control subjects using the types of contraceptives under investigation, these data suggest that there is little or no increased risk of stroke, VTE, or AMI associated with the use of oral or injectable progestogen-only or combined injectable contraceptives. However, further investigation into a possible adverse effect on stroke risk of progestogen-only contraceptives used by women with a history of high blood pressure are indicated.