Concerns about risks associated with combination oral contraceptive pills (OCPs) may limit their use in women over 35 years of age. Most concerns are based on earlier studies of oral contraceptive formulations with a higher ethinyl estradiol content, rather than more recent studies of lower dose formulations. Seibert and associates discuss the need for physicians to address both the risks of OCPs and the misconceptions about this form of contraception when counseling women over 35 years of age.

While use of OCPs increases the risk of venous thromboembolism, the degree of risk appears to be the same in women taking formulations that contain 20 to 35 mcg of estrogen. The absolute risk of venous thromboembolism is very low (one case per 10,000 OCP users per year). Oral contraceptive pills also contain progestins, including desogestrel and gestodene. These two progestins have been associated with an increased risk of venous thromboembolism.

The risk of myocardial infarction may be increased in women using OCPs, especially if smoking (more than 10 cigarettes per day) or other cardiovascular risk factors are present. The association between OCP use and ischemic stroke is less clear, although increased risk has been demonstrated in OCP users who have migraines. There is no documentation of an increased risk of breast cancer in women who use OCPs. One study found a slightly increased risk of gallstones, although the risk was lower in women over 35 years of age than in younger women.

The potential benefits of OCP use in women over 35 years of age include effective birth control, reduced risk of ovarian and endometrial cancers, possible reduced risk of colon cancer, improvement of perimenopausal symptoms, improvement of acne, and increased bone mineral density (although improved fracture rates have not yet been demonstrated).

Before use of OCPs is initiated, a thorough medical history should be obtained and blood pressure should be measured. If a patient has risk factors for cardiovascular disease or a family history of dyslipidemia, a routine fasting lipid panel is recommended. Mild lipid abnormalities do not contraindicate use of OCPs, but lipid levels should be closely monitored. Because OCPs can increase blood pressure, they should be prescribed with caution in patients with mild hypertension and patients who smoke (see accompanying table).

The best OCP to select is the one with the lowest effective estrogen dose. Side effects are most common during the first three months. The most frequent adverse effects are abnormal menstrual bleeding, nausea, weight gain, mood changes, breast tenderness, and headache. Follow-up should include annual blood pressure measurements, lipid profiles in patients with a baseline abnormality, and a review of symptoms that could signify an important adverse effect. To help patients recall possible adverse effects they may have experienced, physicians can use the acronym ACHES (abdominal pain, chest pain, headaches, eye problems, severe calf or thigh pain). Breakthrough or intermenstrual bleeding is common and usually resolves spontaneously after a few months. The incidence of breakthrough bleeding appears to be higher with formulations containing lower estrogen doses.

The authors conclude that OCPs can be prescribed safely for many women over 35 years of age. Physicians should explain the risks and benefits of OCPs for women in this population and should address misconceptions so that an informed decision can be made.