Prescription Contraceptives:Countering the Risks

Abstract

Drug companies have been at work throughout the 1960s, 1970s, and 1980s trying to reduce the steroid content of their oral contraceptives (OCs). Researchers have been successful in reducing steroid content while maintaining effectiveness, thereby making OCs safer. In the 1st half of the natural menstrual cycle, a woman secretes estrogen as the dominant steroid product. In the 2nd half, estrogen is the principal reproductive hormone. Estrogens inhibit ovulation, possibly by inhibiting implantation, altering ovum transplant, or in some way preventing corpus luteum function, which is necessary to maintain early pregnancies and the endometrium. There are still only 2 estrogens and 6 progestins on the market today. They are probably the most thoroughly studied chemical ever seen in the history of pharmacy or medicine. 1 of the estrogens, mestranol, is really a drug of the past. In the body, mestranol is converted to ethinyl estradiol, the other estrogen on the market. Consequently, there is no reason to use mestranol itself. Within the dose range of 50-100 mcg, there's little difference in contraceptive effect. Progestins are the other active ingredient in the combination OC. Their principal action is the thickening of the cervical mucus, which prevents sperm penetration. Also, with sufficient progesterone, ovulation is inhibited, but this happens in only 40% of those patients taking, for instance, the "mini-pill" (which consists of progesterone only). The progestins and the estrogens work in concert to make OCs a highly effective contraceptive method. Recent surveys conducted by the Centers for Disease Control and National Cancer Institute looked into the relative effectiveness of OCs. Nordette had a use effectiveness failure rate of 3.5; Ovral, 3.6. Loestrin 1/20 -- norethindrone acetate, 1 mg, and estinyl estradiol, 20 mcg -- shows a failure rate of 4.5. This indicates that the threshold for an effective dose of estinyl estradiol in OCs is 30 mcg. For 1 mini-pill, Ovrette, the failure rate is 9.5 -- much higher. Depo-Provera has a failure rate of 0.7. The primary complaint from women taking OCs is spotting and breakthrough bleeding during the cycle. 30-50% of women given OCs stop taking them within a year. OC side effects include nausea, fluid retention, breast tenderness, leukorrhea, hypomenorrhea, headaches, spotting around the face, hypertension, and visual changes. 1 of the risks of birth control pills may be cervical dysplasia -- changes in the cells of the cervix. The relative risk of cervical cancer with OCs after 5-9 years is approximately 1.8. Clinical cases of deep vein thrombosis number 1/1000 per year among nonusers of OCs. Among users, the rate is 3 times as high: 3/1000. The most serious potential adverse effect is myocardial infarction. Of the excess deaths attributed to OCs (23.3 total per 100,000 users), 22.7 are due to myocardial infarctions and hemorrhage. The discussion also briefly reviews other methods of contraception -- Depo-Provera, male contraceptives, implants, the diapragm, and IUDs.