Providers often will not furnish a full range of facts when prescribing Combined Oral Contraceptives (COC), basing the information given on their own professional opinion rather than a well-balanced presentation of the data available. Ultimately, it’s your responsibility to read the fine print.
Types of Oral Contraceptives
There are two main types of oral contraceptives: Progestin Only Pills (POP) and estrogen-progestogen pills (COC, or combined oral contraceptives). Of these, COC’s are far more commonly prescribed. “Worldwide, more than 100 million women – about 10% of all women of reproductive age – currently use combined hormonal contraceptives”.1
How COC’s Work
Combined oral contraceptives are blend of synthetic estrogen and progesten. Unlike other forms of contraception that prevent sperm-egg contact, COC’s use a very different, 3-fold approach to birth control. The Physician’s Desk Reference states, “although the primary mechanism of [combination oral contraceptives] is inhibition of ovulation, other alterations include changes in the cervical mucus, which increase the difficulty of sperm entry into the uterus, and changes in the endometrium, which reduce the likelihood of implantation.”2 In other words, if the pill’s first two methods - inhibited ovulation and thick cervical mucus - fail to deter fertilization, its final measure of defense will cause any fertilized eggs to be prematurely aborted.
The pill is 92–99% effective at preventing pregnancy with perfect use.3 With typical use, 8 out of 100 women using a COC will become unintentionally pregnant each year.4 Common medications can decrease the effectiveness of oral contraceptives, including certain types of antibiotics and particularly, St. John's wort. COC Health Risks One thing your doctor probably didn’t tell you is that the estrogen in COC’s is a known human carcinogen, listed among such cancer-causing agents as arsenic, tobacco and asbestos.5 According to the National Cancer Institute, COC’s “increase a woman's risk of cervical cancer, breast cancer, and liver cancer."6 The prevalence of HPV, a leading cause of cervical cancer, is also found to be higher among oral contraceptive users.7
Smoking while using COC’s increases your risk of heart attack, blood clots and stroke, especially in those over 35 years of age. You are up to 8 times more likely than a non-user to develop a blood clot, even if you don’t smoke. The risk is up to 3 times greater for those who use COC’s containing a progesterone called drospirenone.8
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World Health Organization & the International Agency for Research on Cancer. (2005). Press Release #167: IARC Monograph Program Finds Combined Estrogen-Progestogen Contraceptives and Menopausal Therapy Are Carcinogenic to Humans. http://www.iarc.fr/en/media-centre/pr/2005/pr167.html
PDR Network. (2010). Precise Monagraph. Ortho Tri-cyclen, Mechanism of Action. http://www.pdr.net/drugpages/concisemonograph.aspx?concise=1001
Centers for Disease Control and Prevention. (2011). Unintended Pregnancy Prevention: Contraception. Hormonal Methods, Oral Contraception. http://www.cdc.gov/reproductivehealth/unintendedpregnancy/contraception.htm
Centers for Disease Control and Prevention. (2010). Morbidity and Mortality Weekly Report (MMWR). U S. Medical Eligibility Criteria for Contraceptive Use, 2010. Contraceptive Method Effectiveness. http://www.cdc.gov/mmwr/preview/mmwrhtml/rr59e0528a1.htm
American Cancer Society (2011). Know and Probable Human Carcinogens. International Agency for Research on Cancer. Group 1: Carcinogenic to Humans. http://www.cancer.org/Cancer/CancerCauses/OtherCarcinogens/GeneralInformationaboutCarcinogens/known-and-probable-human-carcinogens
US Food and Drug Administration. (2005). Press Release: World Health Organization Classifies Contraceptives as Highly Carcinogenic. www.fda.gov/ohrms/dockets/dockets/05n0345/05N-0345-EREG23-Attach-1.doc
World Health Organization & the International Agency for Research on Cancer. (1999). IARC Monographs on The Evaluation of Carcinogenic Risks to Humans, Volume 72. Hormonal Contraception and Post-Menopausal Hormonal Therapy. http://monographs.iarc.fr/ENG/Monographs/vol72/mono72.pdf
National Institutes of Health, International Library of Medicine. (2011). Estrogen and Progestin (Oral Contraceptives). FDA notice regarding drospirenone. http://www.nlm.nih.gov/medlineplus/druginfo/meds/a601050.html