The contraceptive effect of oral contraceptive use provides an important health benefit, particularly in developing countries, where the risks of pregnancy and childbearing are increased. Several important noncontraceptive health benefits of oral contraceptive use include the prevention of endometrial and ovarian cancers. Data are generally reassuring concerning the risks of oral contraceptive use, which include cardiovascular disease and breast and cervical cancer.
PIP: Current findings and controversies between oral contraceptives (OCs) and cardiovascular disease and cancers. Specifically, venous thromboembolism, stroke, myocardial infarction, (MI), atherosclerosis, breast cancer, cervical cancer, endometrial cancer, and ovarian cancer are reviewed. The concentration in the literature is on higher dose estrogen (at least 50 mg) studies which suggest that there is with current users, particularly older women who smoke, a risk of myocardial infarction, venous thrombosis, and subarachnoid hemorrhage. Of the 11 case control studies and 4 cohort studies it appears that venous thrombosis increases in risk with an increase in estrogen content and remains constant for duration of use. However, definitive studies have not been completed on 50 mg doses of ethinyl estradiol (EE) and mestranol (ME). The actual individual risk may be small, 1/1000 current users/year. Thrombotic and hemorrhagic stroke in the 1970s had a risk of 37/100,000 users per year, mostly among smokers 35 years and older with predisposing medical conditions. It is suggested that although there were mixed findings between current and past users in the 1970s low dose current or past users are not substantially at risk. The pre-mid 1970 risk of MI was 7 and 67 cases/100,000 current users ged 30-39 respectively per year. The risk group is similar to stroke. Thrombosis seems to be responsible for the increased risk, rather than atherosclerosis. More data are needed on low preparations; however limited findings suggest little if any risk. There is no available data on the risk for coronary artery atherosclerosis due to OC use, even though 50% of all women die from atherosclerosis-related processes regardless of OC use. Non human primate studies, however, suggest that there may be a reduced risk, perhaps due to the presence of estrogen receptors in arterial endothelium and smooth muscles. Data clearly indicate that the overall risk of breast cancer pre and post 1950 is the same, but age may be a factor with younger OC users at risk; parity protects. The association for lifetime risk, however, cannot be determined since most use occurred in the 1960s. For cervical cancer, 8 found no increased risk and 9 did, and the suggestion is the 5 years use is related to increased risk. Biases related to sexual behavior confound control and analysis of data. The most common cancer in developing countries is cervical, which warrants greater Pap smear screening to reduce this preventable cancer. Protection from cancer of the endometrium occurs for 15 years following 12 months of OC use at a 40% reduced risk. A protected effect is also found for epithelial ovarian cancer, with a 40% risk reduction. It is concluded that health benefits of OCs far exceed the health risks.