[Health risks of oral contraceptives]

Oral contraceptives (OC) are either composed of a combination of an estrogen derivative (usually ethinly estradiol) and a progestogen, or they contain a progestogen only. OC are characterized by a high effectiveness and have a low failure rate if taken correctly. Most women tolerate OC relatively well, but adverse effects do occur which are driven by the estrogen dose as well as by the type of progestogen. The most frequently reported adverse effects are nausea or vomiting, breast tenderness, headache or inbalanced mood, but these unwanted side effects are often transient. The fear of weight gain of many OC users is not necessarily supported by data from studies which report relatively little differences in body mass index on average during OC use. Nevertheless, substantial weight gain can occur in individual women. The widely discussed fear of breast cancer is also not justified, and the risk of developing ovarian or endometrial cancer is reduced for women who use OC on a regular basis. Venous thromboembolism (VTE) is the adverse effect with the greatest potential for serious harm if pulmonary embolism develops. This rare, but potentially dangerous adverse effect of OC has been discussed emotionally for many years and keeps attracting a lot of public interest. VTE is rare in young women, but the VTE risk is increased two- to sixfold for OC users as compared to non-users. The VTE risk increases with increasing estrogen dose, is highest in the first year of use, and is higher for OC from the third generation (containing desogestrel, gestodene or norgestimate) than for OC from the second generation (containing levonorgestrel) or than for the progestogen-only pill. According to most studies, OC containing the progestogens drospirenone or cyproterone acetate are similar with regard to VTE risks than OC from the third generation. Individual genetic susceptibility affecting the clotting system plays a major role in the risk of developing VTE in combination with OC, and smoking is also an important contributing factor to an increased VTE risk for women using OC. It is important that doctors and pharmacists inform new users of OC about potential health risks of OC use, and that the personal and family history of previous health risks is assessed thoroughly in order to rule out that important and relevant contraindications are present when a women starts taking OC.